Currently Online 
How long to beat is indeed invaluable, I use it always before a purchase and base what I buy off it. Like No body wants to die is a game I want to play but I don't want to be in it for so long but when I seen on HLTB that it is 6 hours, it's an instant buy for me.
Consoles are now incorporating stuff like this in with activity cards on PS5 or the percentage meter which is often inaccurate (it's more like a loading bar that stalls from time to time) but it's better than nothing and I want to see features like that going forward but data gained from players who opt in and not QA so it can be more accurate, it's great to finish a mission in FF16 and while consider if you want to play the next mission with it's estimated time on an activity card. You'll be like, fuck the next missions a long one, might as well end it there and do an Astrobot level. It makes juggling games feel as good as maining a game.
As for stuff that isn't mentioned in the thread, a simple timer on your phone to be able to accurately record your gaming time so you don't have to rely on system clocks that are ticking over while the games is idle and you're AFK. For me, knowing how much I play accurately is very important and I really wish PS5 was more accurate, the games on the dashboard are so wildly off by absurd ammounts like doubling your game time and while the games list is more accurate it should stop ticking when the game is paused so it doesn't over track and in game clocks don't count the time you die and reload a save so they end up under tracking.
Forum threads on here, below in my sig are also great to keep you on track and give your self a goal to prevent falling into a rut or wasting time with games you aren't enjoying or switching out your main games too much. A simple thing that really helps with time management and preventing burnout.
Essay Pro