I recently shared a time-saving expression that I cobbled together some time ago, which has saved me tons of time and keyframes over multiple projects.
Basically, it allows you to bring in tons of layers at the same time, & control them all with a few sliders on a single control layer. It’s great for adjusting the timing of a lot of layers at once. The best part is that, once you’ve created the setup, you can copy and paste this to any new composition & your layers will essentially animate themselves.
The good people at AEtuts+ have the tutorial over at their site. Hopefully it helps you as much as it has helped me.