what do you do with old yucky bathroom fan?

[Mark Wallis]

I probably spend less time making decisions on big ticket items like roofs, kitchen cabinets or flooring vs bathroom fans!

I seem to spend a lot of time researching bathroom fans. The homes have them but usually they are gross looking and sound unbalanced and rattle. Finding names and model numbers is not easy. Sometimes I get lucky and find a replacement kit online that fits. Other times I try to get Lowes or HD kits. Maybe I'm working too hard at saving a few bucks. Should I just get a whole fan box assembly and have my guys do the necessary framing and drywall repairs for new?

Looking for advice from those who have a better solution.

thanks!