Frequency:
Check every-second week/once a month.

Check sporadically for larger cuts in the tread or bulges or cracking on the sidewall as this indicates a replacement is due.

Method:
‍1. Check the side of the tyre for max tyre pressure. The max pressure can be found on the side wall of the tyre.
2. Pump the tyre to just under the maximum indicated pressure, perhaps consider lowering pressures for more grip in wet/colder weather.

Tire sizing:

Maximum tire sizes:

eBullitt, Ep8 and E6100: 26 x 1,75" rear and 20 x 2,20" front

The Original Bullitt: 26 x 2,0" (32 mm when using 700c)  rear and 20 x 2,20" front

Note:
The majority of Bullitt models are spec’d with the Schwalbe Marathon tires, recommended pressure of 60 Psi/4bar, but always check before inflating.