When do people who work full time run their errands?

Laugh at my naivete. Please. I deserve it.

I have my first full-time job. I need to mail a letter. I need stamps. I scoped out the local post office but its hours are weekdays 9–5 which are precisely my hours. I got to thinking, those are my doctor’s office’s hours too. Lots and lots of businesses’ hours.

If you work full time, when do you run errands that involve businesses that work the same hours as you? Do you have to use a vacation day? What if you’re someone who gets regular therapy or something; you can’t very well take a vacation day every week?

I just need a stamp. I’m not taking a vacation day to get stamps.

Just one stamp. :(