In my experience, replacing every 2 years is pretty standard, when using mold resistant caulk (otherwise would be every 6 months I suppose)
I've tried the caulk-be-gone solutions for supposedly making removal easier, but it didn't work well for me. To make removal easier, use more caulk. Thicker lines won't snap when pulling and you should be able to gentle pull large portions. It's the super thin lines of caulk that takes all the work to remove.