How long will it take to replace the alternator on Chevy astro?

it depends on the vehicle but usually 5 minutes to 15 i have personally changed several myself and im not a mechanic by trade. Most have 2 bolts and a tension bolt for the belt

some cars require the radiator and the a/c condenser to be taken out just to see the alternator (2000) cadi deville book time is 3 hrs plus a a/c recharge and coolant flush. i wouldn't say 5 or ten minutes all car have a labor guide for all labor related repairs chilton and motor manuals you can go to a public library and get info on disc or books . i repaired autos for 35 years and you would not believe the places they put these things average time is 1 hr. and includes load test and alt output test