We just adopted a lovely 3 year old tom (neutered) and he's currently up in our bedroom with litter tray in the en suite. He's staying there a couple more days to get used to the smell of the new house and then we'll let him into the rest of the house. I'm bringing the older boy up for frequent visits (younger boy is blissfully unaware of his presence for the moment).
The home check person said we must keep him indoors for 'as long as we can stand it' but she said, certainly at least 8 weeks. 
Really that long?! It's true that he was (mostly) a flat cat before (he came from a good home but they didn't want to keep him with two very young children, in a flat, any more) and I'm obviously a bit worried that he won't be used to going outside, so when the time comes we'll let him out when he's hungry and for short periods at a time.
So how long would experienced rehomers keep this cat indoors? It's going to be a real strain with windows and doors to the outside staying shut, not to mention two children who will want to be in and out of the garden when the weather's nice.