[tptacek]

I've had people straight-up tell me during interviews that they're leaving their current position because they've reached either their one-year cliff or their four-year package and want a new opportunity with potentially higher gains.

The person who told you "I'm looking because I just hit my first-year cliff" actually told you "DO NOT HIRE ME". Listen harder.

People do leave when they hit four years. Four years is a long time! Some teams are O.K. with this, but if you're not, there's no reason to mess with vesting to solve the problem; just grant them more of the employee pool to stay.

Everyone is always looking for better opportunities. That's fine. Be the best opportunity for everyone on your team, or get better at recruiting. Vesting can't help you with this problem, but it sure can hurt you.

[loceng]

Makes me wonder how hard they worked those 4 years, or perhaps just that last year they didn't necessarily care to be kept on afterward.

[j2labs]

If they were there four years without being let go, the company was clearly fine with the performance.

[tossit1234]

Makes me wonder about how their investment in effort has carried out over that time. I'm sorry, but X shares over Y time with additional investments of A, B or C, usually means X means a lot less (percentage-wise) for a continuation of effort.