I have a couple 1TB+ folders between two different setups where I continually clip a lot of cool or funny gaming moments, thousands of them over the past several years.

The last time I tried “backing them up” (just by copying and pasting in Windows Explorer from folder to external HD) took a whole night, which is fine… but the following week when I tried to “update” it with just the new clips it wanted to do the entire overnight process again.

Which brings me to my primary question: What is the simplest “incremental/differential” software solution I could use for this specific case? Ideally free but I don’t mind a relatively affordable one-off payment either if the UI is really nice; I’m a sucker for good design.