Tension Loss of The Racket Strings
For starters, what level player are you? Typically, beginner players (2.5 to 3.0) can tolerate larger changes in tension than intermediate to advanced players (3.5 to 4.5+), simply because beginners are less proficient at perceiving changes in their stringbed. So if you’re just starting out, two-month-old strings may be fine to knock the ball around with. But if you’ve been playing for some time—which I imagine you have—you would do well to restring before hitting the court post-vacation.