I've been using SRAM apex on my winter bike for a couple years now. It's performed well so far, but recently I'm noticing that it's becoming easier and easier to shift 2 gears when you only want to shift one (only really affects down shifting into lower gears). Or, if you want to shift 2 the rear mech shifts 3. I know the anti-SRAM lobby will say that is just SRAM, but it doesn't happen with the force groupset on my good bike and it never used to happen in the first 12 months of using the apex.
I know you can adjust the reach of the levers, pretty sure you can't adjust the sensitivity though right? Is there anything that can cause this? Build up of dirt maybe? The cable tension is bang on, if I'm careful it shifts precisely and returns perfectly too. However, in a bunch ride in the pissing rain going up a snakey climb I find that precision doesn't come quite so easily.
It definitely used to be way better, so I'm convinced it's an issue that's become apparent over time. Hopefully there is a cure though!