Should I clean out my Trash or Downloads folders regularly?
For sure, both Downloads and Trash are good to keep eyes on. The productivity nerds would say that ideally one keeps both folders empty, with the idea being that anything important enough to keep gets stashed somewhere else.
Less compulsive Mac folks might simply say that too many files in a folder can make Finder squirrelly, so keeping it under 500 files and definitely deleting bigger ones quicker should keep you running smoothly.