It’s always good to start saving in a 401k to get the contributions if your job has it. If not it’s recommended to save enough to have your salary saved (invested) by 30 and the earlier you start that the better. It all depends on you though and how long you want to work haha. Mostly as long as you have some banked for rainy days you’re mostly fine but make sure you budget well or you could end up worrying about money later which isn’t something anyone wants.