I agree that there are potential issues with having unlimited time to edit. I don't think though that 90 minutes is long enough.

The reason being my very ancient computer. I still use dial up and there have been many times when I have had to leave and reboot so that I could edit a post. By the time I log off and reboot and then find my way back, 15 minutes is not near long enough. And if I get side tracked by one of my kids then the 90 minutes isn't enough. Life does happen and we do get interupted.

My two cents.

Laura