Well only sets I started and completed this year was the Peace dollars and the 20th century type set. BUT I started the small cents in prior years and completed that one this year (1857 to 2019, all mints Eagle, IHC, LWC, LMC and LSC) and the Mercury dimes I'm still missing the 16-d. I've been busy. This is what happens when I lost interest in one hobby (astrophotography see below) and started another one. Also helped that I had extra telescopes not being used.
I started with coin collecting in 1958, and collected mostly US stuff until around 2000. By that time, the US coins that I needed became too expensive (early US gold, for example.) Then DSLRs became available, and I became interested in astrophotography. Eventually, I got too old to lug around heavy mounts and stay up all night in the cold. I concluded that it was better to quit astro before I threw my back out, rather than afterwards.
I switched back to coins, joined CCF in 2015, and started collecting mostly foreign coins.