Time bases (such as Crystal oscillators in lab equipment) suffer from a range of error sources.
(1) Drift causes the oscillator frequency to shift over time, mainly caused by temperature changes
To avoid drift, the main thing that needs to be done is to counteract the effect of temperature. This can be done passively by allowing the time base to reach operating temperature prior to usage, by using an external time base that is built to internally offset temperature differences (TCXO), by using a heated time base (OCXO), or by switching to an external high precision source directly (such as a radio station or a rubidium oscillator).
(2) Accuracy causes the Time base to produce a timing signal which has a higher or lower frequency than the real reference value
This can only be avoided by directly or indirectly linking to a signal which is defined to be accurate, in other words an atomic clock. Surprisingly this is simpler than one would imagine!
(3) Synchronisation errors occur if different lab equipment is used together which uses individual (internal) time bases. Accuracy in such a setup will be limited to the weakest link in the chain.
The first step here should be to link the equipment time bases together if possible or at least regularly manually calibrate the instruments to a master source.