It was a lot of work replacing my well shed. The cement blocks were shot and the upper lean-to was only standing because the carpenter ants were holding on tight. I just couldn't stand not having it look nice and be useful. Foundation being 8'x8' gave me something to work with. I had to replace a lot of blocks, then I inserted rebar and filled it with cement. 24 bags hand mixed and bucket poured. Fortunately my neighbor, who would have been 97 today if still with us, was a union trained carpenter and electrician. He taught me enough about framing and roofing to get by. Every day as soon as he heard me start work would come out and made sure I did it right. You better believe my foundation was level and square. Got to love retirees. I'm one now.
I added a section to the well pipe. Original was only a few inches above the floor. New code requires at least 18' high. I also put a sump pump and pit in. With the water softener out there I needed something to deal with the water it puts out when cycling, plus one year when we had a horrendous 100 year storm and 3' of water in the pump shed floated the well tank and pipes connected to it. Plumber came and pumped it out and repaired the piping. I was lucky he could come that day, he had a lot of calls coming in from the storm. Quite expensive. Back up generator and transfer switch keep everything running now.
As for the foot valve, it was a very slow leak. In my case I have noticed if I'm losing a bit of prime, the upstairs toilet will give a puff of air when flushing after sitting overnight. As I mentioned earlier I just put a new foot valve in. The date stamp was from 9/18 so about 7 years. Life span is different depending on water Ph type. Mine is hard water, and I get a bit of green buildup from the minerals. In the future I will change it every 5 years.