For the few months after starting TFP a couple of years ago, I actually tested twice per day - once in the morning and once in the evening! lol Now that is overkill, but it was fun as it was my first pool, I didn't mind spending a little more for reagents and I was able to really get a handle on how my FC levels reacted to a variety of use and weather situations. For the rest of the season, I tested once daily.
The second season, I tested every 2 - 3 days, while still making daily additions of liquid chlorine. I've never gone below my minimum nor have ever had algae and had to slam my pool. I only tested pH weekly, as I find it's very stable.
This year, we had an SWG installed, so I'm back to testing every day (only once) as I get it dialed in. I'm hoping in the near future I can test weekly, but I'm not quite ready for that yet! I say, do whatever you feel comfortable with.