Best way to speed up my old Android phone without buying a new one?

I've got an Android phone that's about 4 years old now, and it's been getting slower and slower. Apps take forever to load, and sometimes it just freezes out of nowhere. I’ve tried clearing cache and uninstalling some bloatware, but the improvements are minimal. I’m not really looking to buy a new phone just yet. Has anyone found some good tricks or apps that can help boost performance on older Android devices? Maybe some settings tweaks or lightweight launchers? Also, if you’ve tried custom ROMs or rooting for speed, I’d love to hear your experience with that. Was it worth the effort or just more hassle? Any advice or personal success stories would be awesome!