The only reason for a 'periodic check' of brakes IN THE PAST was to inspect the linings for wear, so that metal would come into contact with metal and score the surfaces, necessitating more costly machining or replacement of the scored part.
Today, the BMW is equipped with wear sensors which will light up a warning on the dash and let the driver know he needs to get new brake pads. It is possible, nevertheless, to avoid the additional cost of replacing the sensors (once the wear light turns on, the sensor has to be replaced) by replacing the pads in advance of the sensors making contact, and a visual inspection by the mechanic has the possibility of alerting the owner that 'your pads are close to worn down' (i.e. "pad is thin, but sensor has not yet made contact").
Other than as described above, there is no yearly 'brake service' needed. There is, according to BMW recommendation, the need to replace the brake fluid every TWO years, because the brake fluid absorbs water, and water reduces the boiling temperature of the brake fluid, and BMW feels that more than 2 years means a dangerously low boiling temperature, leaving your brakes ineffective in times of emergency. (Other manufacturers have their own brake fluid change intervals, running from yearly to every 3 years to (in the case of Toyota) never :tsk: !)