How can I check if I actually need more RAM before buying it?

Run systeminfo or open Task Manager (Ctrl+Shift+Esc) and check the Performance > Memory tab to see total installed RAM. If you have 16GB and your usage is consistently below 12GB in Resource Monitor, you’re fine — the bottleneck is likely an old hard drive or too many background apps, not RAM. Only upgrade to 32GB if you’re pinned at 14-15GB usage and running VMs or video editing, and confirm your motherboard supports it first.