Alyus :
Casual games like Skyrim and such... And who is 144Hz monitor designed for? Competitive PvP gamers?
If you get G-sync/free-sync capable monitors, get the highest hz you can, as it will allow much higher framerates without tearing.
If not, I'm someone who plays games for most of the day, being League, RTS', emulators, a few FPS, and KSP.
I've only ever had the luxury of 60hz monitors, but if you can go higher for a minimal investment, that's recommended. Try and figure out your average FPS you get in games and go north of that for hz (hz is frequency, but as it stands with monitors it's essentially the same thing as FPS capabilities)