Depends where I'm going, 5 minutes or less for a non-commute ride, all I have to remember, is phone, wallet, keys. The rest is already attached the the frame of the bike.
For my commute I also have to remember, laptop, lunch, change of clothes, where i put my bag, where my, wallet, phone and keys are. Then I have to go back for my phone. So around 10 minutes usually.
Also helped by the fact that I don't generally wear cycling specific clothing, just what I happen to have on.