So, I ordered product, domestic and with an estimated delivery time of 1-2 working days. It's been 4-5 working days, varying on whether my area gets mail delivered on Saturday which I am not sure if we do.
At what point should I start assuming my mail ain't coming? I've not had a lot of experience with national mail carriers so I don't know if these kinds of delays are to be expected.
You haven't stated what domestic means, so we're fairly safe saying you're an American - probably U.S.
If so, your postal service is a bit of a mess. I think you have Colombus day there, and we'll assume the postal service took a 'long weekend' and were a little lax. Wait til it hits seven working days, give the vendor a nudge, stress a little after ten, write it off after fourteen.