If you are pro yes, is necessary. 40.000$ is not enough money to pay someone their salary and cover travel expenses. Plus you need to pay a sh*tload of money on airports extra baggage for the stringing machine.
And there's few pros that can afford 40.000$ year to someone to take care of their racquets, and P1 are best, so thinking wisely P1 has a great performance/cost relation.
Nostradamus is Fedace http://bit.ly/18gy8uV
4x PRINCE Michael Chang Graphite OS LB (1.40mm nylon @ 24kgs)