[dangelo]

At Quora we decided not to have a higher "minimum service period" aside from the standard 1 year cliff. The rationale is that the vesting cliff is what everyone is expecting as the minimum. If a company wants to have a higher period before someone can leave and retain their stock, they should just increase the cliff to that length of time to make it fully transparent.

[abalone]

That's a fair point, but cliffs are more severe than exercise windows. Many employees still get to keep some of their equity in a 90 day exit window scenario. I think Kupor modeled it at about a third of vested shares on average.[1]

More mature startups may be able to simply abolish the long-term incentive that the 90 day window provides, but I suspect younger (<30 employee) startups need added turnover protection. Perhaps backloaded vesting would be a more comparable replacement? Transparent, predictable, fair, and not as harsh as cliffs. You keep what you vest, but 70% of it vests in years 3-4.

[1] (Although there's certainly unfair variability based on personal financial circumstances in that average.)