Everyone is different, but the key is to find your own personal balance between your drive to get better and the overall enjoyment you are getting from the game and tournament scene at the time.
There are also a lot of other things you can do to minimize your need for smash hiatuses:
- Experiment with other characters
- Practice with different players or in a new location
- Learn new tech or matchups
- Find a new player or tournament series to study
- Set other small, attainable short-term goals for yourself that help you stay focused and give you fulfillment for completing them
- Make some changes to your non-smash schedule or commitments to give you more free time or reduce stress
Sometimes though, nothing beats just taking a break from the game for a while. You might focus more on another game or hobby instead, socialize more, or whatever you think you need during this time. There's certainly nothing wrong with having a hiatus once in a while, and sometimes you can come back even more refreshed than before.
Ultimately it's up to each person to figure out what kind of lifestyle choices work best for them. Some may even take it a step further and quit the game all together, and that's OK too. A hobby is a hobby. There's an unlimited supply of them out there. Do what you need to do. There will be plenty of people waiting and still playing if you decide to come back in the future.