I'm still learning so pardon the dumb question. In wiring a new addition for 110v and 220v electrical outlets, switches and lights is there a certain time when you would want to use stranded core THHN wire vs solid core THHN wire? I guess in particular I'm referring to when you would use something in the 12 or 14 gauge size.

I'm running counduit throughout in my new addition and when looking for the feed wires on spools the store carried both stranded THHN and solid THHN in both 12 and 14 gauge. Pricewise they both seem very comparable.

Thanks,
Royce M