[joshu]

two to three years, typically.

[eladgil]

I think it really depends on the company and context. E.g. if it is truly an "acqua-hire" for team members only, it is 4 years. If there is some IP, asset, or expertise thrown in the timeframes can be shorter. It also depends on the company doing the acquiring....

[tptacek]

That sounds right to me.

[rachellaw]

that was what i thought too. four years seems particularly long.