If you want to get into comp tf2 it's obvious that you have something competitive about yourself, if you have that you will invariably want to get better, to get better you will need to practice a lot, practice takes time...
It's all a bit redundant because if you're really interested in comp you will spend time on it, how much it depends on you, but if you enjoy it I wouldn't consider it time wasted, obviously there are a lot of priorities in life and things change sometimes.
When I got into comp I spent a whole lot of time doing comp related stuff and practicing, but I enjoyed it, sometimes I went too far and messed my priorities because of it but it depends entirely on you, on how you can handle that and set limits for yourself. You can have a set and planned schedule and you can still get better without wasting all your time.