When it comes to longevity of strings, there are many factors. The main factor being the type of string used. If you’re breaking strings regularly, then maybe you should be using a more durable string. If you’re using a synthetic gut, changing to a Polyester or Hybrid (Polyester mixed with a softer synthetic or multifilament) will allow your strings to last a bit longer.
Racket’s will lose about 30% of their tension within two weeks after a restring. Therefore, you need to get your racket strung far more often than you might think.