first off- its worth it.
also, the first levels are very quick, it takes longer as you progress...eventually it takes about a couple hours to levell of just casual play, and later levels take several hours. getting from 70-80 can take about 3-6-10 hours to level...iirc.
its easy to get absorbed in it, they have had it for years, and have worked out most the kinks in it. you dont lose items by dying, just have to go from the graveyard to your body.
i played it for a while, it was the reason i left here way back when and i just quit recently. if you have a social life or family, you should limit what you do on it- i was running wiht groups of people which make it hard to pause if i need to make a bottle or change a diaper. you can get to 80 without grouping, but the best gear requires groups. they made it time-friendly, so most decent groups can clear most places in 30-60 minutes, but depends.
it is fun, it is addicting, and right now i dont miss it, but if i do join again, it will be a very limited basis.
also- you dont get xp while away, you build "rest xp". rest xp gives you 2x xp from killing things until you burn it up.
fyi- cake is a lie.