refresh of items in a shop

[Reitermaniac]

After how many days does the iventory of the different shops/caravans change? Do I have to avoid these shops for this time or changes their inventory constantly?

[gsmanners]

I think the general rule for shops is once every three days and caravans refresh twice a week (although I don't remember off hand which days of the week). I seem to recall that caravans sometimes get buggy and don't always refresh when you think they should (although that's my experience in Fallout 3, but this game is really just FO3 with some small additions).

[Wertoret]

72 hours for most respawns and shop restarts