I started having regular performance problems with Firefox when I switched from verizon's email web site to aol's. I always have my aol email session going, plus various other sites. I find that after about a week, my Firefox session slows to a crawl. I delete cookies, clear the cache, and my performance is fast again. I lowered the cache limit to 100 MB, but it hasn't made any difference. A couple days ago, Firefox slowed after I had deleted cookies and cleared cache only a couple days before that. Can you suggest a more lasting resolution? Plus, I would like to keep some of my cookies.
I have an HP PC with Windows 10.