Water changes?

I do a 50% weekly water change.

Roughly 25% weekly. If I happen to skip a week, then I'll do 40-50% the week after. But honestly, that's probably more than is needed, at least in a planted tank. A few years back I had a RCS breeding colony in a 10 gallon that at any given time, had between 150 and 250 RCS in the tank (counting both babies and adults). It was a really, really busy time in my life and I went probably close to a year doing only a 50% PWC once per month. I never had problems with shrimp deaths and they never stopped (or even seemed to slow down) breeding. The tank was moderately planted and, most significantly, had a boatload of java moss in it, so I think the plants sucked up the extra nitrates and prevented them from ever reaching levels where they would bother the shrimp. I would never recommend anyone neglect their tank(s) the way I did, but it does illustrate that some of the shrimp species are actually quite hardy.

Aiming for 20-25% PWC weekly is probably a good goal.

I have 2 heavily planted 10 gallon Cherry and Yellow Shrimp tanks that I haven't done a water change in about 2 months. I just top off once a week. Both have Aquaclear HOB filters with sponges on the intakes.