In rambling fashion here are my thoughts for what I did in our backyard (and some of what I wish I had done/could do):
PRELIMINARY: Don't get a pool if you are not planning to supervise it. Don't buy a pool unless you can also afford a good test kit, or at least the FAS-DPD, pH, and CYA tests. Don't buy a pool unless you can also afford to put your kids in swim lessons at least until they are proficient at floating and treading water.
1. Figure out the best part of the yard for a pool. Think in terms of if you prefer it with shade; if you are okay with pine needles/leaves; how far from gas line into the house; if you want the neighbors to see you or if there is a more private part of the yard; if you can see it from the kitchen window (VERY useful in my experience); etc.
2. Figure out the largest "seasonal" pool size you'll ever want. Intex makes a 16 x 32 foot rectangle and a 26 foot circle.
3. Have a concrete pad poured that is at least a little larger than the footprint of the largest pool you'll ever want. The bigger the better on the concrete. YOU WILL NEED TO HAVE IT BONDED (adds little cost, adds some time to coordinate with electrician, but worth it imo especially because it seems like the more prevalent Intexes are becoming, the stiffer the regs relating to them - so might as well do it out of the gate instead of chancing someone telling you to do it later which is difficult). CONSIDER pouring a four inch curb around it if you live in a region where you could have an ice rink in the winter -- if you go the route of the curb, have them put in some drainage points -- also, in deciding if a curb is a good idea think in terms of if it will also be a basketball court and if so, be sure to allow plenty of space so no ankles are broken on the curb. When deciding the SIZE of the concrete, think in terms of it is good to have it extend past the sides of the pool to house a small wading pool for feet-dipping before entering pool; it is good to have floaties on the pad not the grass; if you make it big enough, the kids can ride trikes, scooters, etc around the pool like a track. When considering the SHAPE of the pad, think in terms of you will like this more than you thought and will be glad you made it aesthetically pleasing because it will be a hub all year. When considering HOW to have it poured, think in terms of creating a four-square court in the middle of it even if you are doing a circle. Just have them cut in the lines even though it will look odd -- it will get used. When considering how to PLAN for the future when it comes to the concrete, have them put some conduit in it going through it like an "x" so you can push wires for lights, electricity, etc down the road as you get more money and realize that this is indeed a hub year-round. Also, think in terms of how you plan to use your solar cover. I wish I had some sleeves in the ground flanking the concrete that I could put poles in to support a solar cover reel. Then when the pool comes down I can remove the reel supports and my basketball/roller rink/four-square court/etc is unencumbered. I have not yet devised a reel system and our pool season is so short that so far my husband and/or I have suffered with manually removing this monster -- we push it off onto a picnic table to the side of the pool - so make the pad big enough for that if possible.
4. Buy the pool and use it un-heated for as long as you like it, or until you get enough money to heat it. THEN buy the heater (gas or heat pump, or if you are in a climate nothing like mine, solar). When you buy the pool, buy a solar cover. Never used it, buy my understanding is if going unheated, the Intex Sand filters are plenty good. Use that til you want a heater. When you want a heater, buy the larges filter you can afford, buy a two-speed pump, and buy a 400,000 btu gas heater or equivalent heat pump. Figure out before you buy the appliance if you will need gas or a new electrical panel run to the pool pad - that can get pricey (still worth it, but you don't want to get halfway in and then get surprised by the mounting one-time costs of installation).
5. Buy riding toys. Lots of them - our kids' favorite (and every guest's favorite) are -- for 4 to 7 or so, an EZ Roller and from 7 to12 or so, a Razor RipRider. They eat lunch on them, they play tag on them, they use jump ropes as reigns and play horses by pulling a kid behind them, etc.
6. Get a basketball hoop when kids old enough. If you think you'll want to use it in conjunction with the pool, get it bonded and consider a permanently installed pole. We have a moveable, height adjustable thing that we don't yet use with the pool - but as the kids get older we think we will start to, but will need to figure out how to bond it.
7. Get into the habit from day one to make a few pool rules that you REALLY MEAN and don't sweat the stuff that is not safety-oriented. NO ON EVER SWIMS ALONE; NO KID CAN ENTER THE POOL UNLESS A PARENT LOOKS THEM IN THE EYE AND SAYS, "YES, YOU MAY GET INTO THE POOL" this prevents the parent from absentmindedly saying "yes" when they are doing something else and the real request is not registering; THE LADDER MUST GET REMOVED WHEN THE LAST PAIR OF SWIMMERS GETS OUT every time (we bought a better ladder that could "lock" but it is too tempting to assume it it locked - better for us to remove the ladder and be able to glance out and KNOW the pool is closed; NO GLASS IN THE POOL; AND IF A KID THINKS ANOTHER KID IS IN TROUBLE THEY MUST YELL "EMERGENCY HELP" UNTIL AN ADULT APPEARS (which should be quickly since kids need to be supervised even if good swimmers) AND IF THERE ARE THREE KIDS IN THE POOL ONE NEEDS TO GET OUT AND FINDS A PARENT even if it means going inside without drying off AND LEAD WITH "EMERGENCY HELP" and do not lead with: Billy was swimming with us and he forgot his goggles so he went home to get them and then when he came back he was eating ice cream so we told him he can't have that in the pool and when he got done eating it he started to get on the ladder but Mike was on the ladder so then Billy had to wait and then when he got on the top of the ladder he jumped off, and, wait, I think it was a popsicle not ice cream, but when he jumped into the pool he yelled cannonball but I don't think Mike heard him or maybe he did hear him but he couldn't get out of the way and I think Billy might have landed on Mike because Mike is looking down in the water but isn't really moving.
8. Get creative in tricking out your set up. We have a cheap projector from Kohls. Hang a sheet on the shed and watch outdoor movies in the pool. For speakers we use two old 900 mhz (I think this is right) that I prefer to blue-tooth. They are outdoor and can get wet and are about 25 years old and still work great. Can put them right by the pool and the movie is not disruptive to people on the patio.
WHAT I'VE LEARNED ABOUT HOW AN INTEX CAN GROW WITH YOU:
1. The ultra series seems significantly "better' than the blue and white ones, but the blue and white ones got us just as wet. We have had Intex ring pools, blue and white frame, and two shapes of ultras. All work. BUT I would not do the ring again - I like the straight sides of the round framed pools. What I learned is that you can significantly under-fill a round framed pool and have not problem other than needing to watch pH because when the return was above the water line it acted as an aerator. Draped a flour sack towel over it and that cut it down a lot. Or could simply cut in a lower return and then patch it later - or, if getting a heater, having two returns is not always a bad thing even if they are right by each other (lets the water get out of the heater faster and would probably prevent some of the overheating problems we have seen). This means when you have three year olds you can still buy an 18' round and fill it to under their chins. The next year same thing, but water depth will be higher, etc. We did not know that so started with a 10' round 36" deep pool - it worked, but we could have had a bigger pool sooner (and saved money) if we had just bought a bigger one and under filled for a few years til the kids stretched.
2. The rectangle pools are awesome, but I think less wise to under fill by a large amount -- the sides lean in a bit as opposed to being straight up and down like the round framed pools -- however, I do think you could under fill a rectangle by 15" or so -- we did for quite a long time last year because pool boy was delayed in coming out - so the water sat below the lowest hole and the kids still swam and it seemed secure enough -- but my kids are admittedly not rough-housers so ymmv.
That is the start of a pretty good childhood and stay-cations every weekend all year long. We are fairly home-bound due to some medical considerations, so we put our vacation money for about two years into the backyard and have not regretted it one bit. Pool went up last Sunday (put down foam insulation that gets stored in a stack and covered with a tarp in the side yard not very visible to neighbors; then pool was assembled and moved into position ensuring hoses would reach from the equipment pad; then filled for parts of two days; then pool-boy came out and hooked up and fired up equipment on Thursday; by Friday after work the pool was 90 degrees and we (and every neighbor kid who had ears) swam for several hours on an over-cast evening when no other AG was usable because the water was mid-70s.
For us, we could not afford an in-ground (and our lot is not huge so that would have been a waste of space most of the year) and we had very young kids when we started to enter the pool world so we felt like an AG was safer anyway (harder to fall into without being noticed). So we had "x" amount of money to commit and decided we could spend a lot on a permanent AG that in the beginning would have been way too big for our young/short kids and which would eat up a large part of our yard year-round but only be useable 3 or so months per year. OR we could let the pool grow with us and put the money in the yard itself, not the actual pool. This recipe is not "cheap" per se, but we think it got us A LOT of bang for the buck. I can't express how much our kids and their friends love the concrete pad. Pool season is bitter-sweet because they love having the concrete for four square, sidewalk chalk and paint, roller skating, riding toys, they just prefer it to sitting in the grass if they are chatting with friends; great for fire pit in the fall; basketball court; moon sand next to water table; watercolors and paper; fabric paint/tie dying without care of any mess; etc. Best part for me is I can see it from my dining room and kitchen so I can monitor the pool and what is going on in non-pool season without really intruding (my kids are old enough to swim without me in the pool, finally - for years and years a parent had to be in with them so don't think we just watched from the window when they were little).