to re-use and save or to just bite the bullet

[photo2u]

I am planning in installing new salt generator and new pump to my existing Pentair DE filter and Raypak gas heater. Currently I have a 1 ½ PVC pipes with 1 ½ copper coming out of the heater and from the original underground (Pool made in 1972). Since I am planning to run my Pentair 8 speed pump at a very low volume/speed most of the time, I was wondering when I cut and redesigned the plumbing, should I reuse re-use some of the fittings and valves? Or should replace all my valves and fittings for an all 2” new plumbing. (The 1 ½ copper coming out of the ground will do to its nature of being underground will not be changed). Money is not abundant but I truly do not want to a Mickey Mouse job just to save 200.00 dollars.
Please advice,
George

 

[JasonLion]

My theory is to either make the absolute minimum change, or replace everything you possibly can, to each section of the plumbing separately. If you can get away with a small change then go for it. As soon as you need to replace more than one or two things in some section of the plumbing, just go ahead and replace that entire section with a nice clean new layout and new valves. Hope that makes sense.