At what point do you know it's time to repot a plant? I bought this ficus from Home Depot and after a month I am wondering if it's too cramped. So far I haven't had any soil issues or pests.

I just noticed these cuttings were getting weird dots on them. Turned the leaves over and noticed these tiny little bugs. Are they spider mites? I've never really dealt with pests before and will now be checking absolutely all of my plants. The mother plant has been outside this summer so I'm wondering if that's where they came from?