— A quality test LP can assist in setting the antiskating right.
Strictly speaking, it's not absolutely necessary. Antiskating is an approximate setting that doesn't need to be "dialled in" exactly. But, unfortunately, the antiskating scale on the tonearm can not always be trusted. In my personal opinion, knowing your antiskating is set right is worth the price of a test LP.
Any unplayed brand new test LP that has antiskating setup tracks is fine. Do not buy used test LPs — you never know if the tracks you need are still useable. The three most popular test records are
The Ortofon Test Record,
Hi-Fi News Analogue Test LP and
Analogue Productions test LP.
Please do not use a test LP to set anything up except the antiskating (and the turntable speed if you must). The setup methods offered by the test LP manufacturers are often questionable, and the quality of the signal tracks on the discs varies. It does not matter much for antiskating, but for azimuth you can get
very far out of alignment if you follow the test LP instructions.