A p-sheet might say 24 but you can go 48. No recoat nessesary on solids. Metallic I'd recommend recoat for sure.
Like Clark said I wouldnt normally have a reason to walk away for 24-48 so it doesnt matter. But there have been times i base and take a 3 hr lunch, come back and pick up where i left off.
Edit: i spray ppg dbc and have used the 24 hr scuff no recoat method. No issues. Ive been spraying cars for 15 years.