Originally Posted by
gobaers
... If it's one PNR the bags should interline all the way to your final destination.
For UA policy (max 12 hours or not overnight), 1 PNR or separate makes no difference. UA experiences is inconsistent (what's new) and may be more flexible for UA elites. But best to assume negative and be please if UA will.
Originally Posted by
sweetsleep
It should be possible to place your checked bag(s) in a secure left luggage area for a small fee regardless .....
That varies with airports, such as ORD, among others, has no on-airport options. Fortunately SFO, does.