In an R22 whilst testing the Strobe lights and warning lights work as part of the pre-flight, I always click the clutch engage/disengage switch on and listen for the belt tightener wurring (and then turn it off again obviously!).
That way you know that after spending all that time and effort going though checks and procedures to get the engine running, the bloody belts are going to tighten up enough to drive the rotor blades....
Usual cause of it not 'wurring' is the fuse has gone - its the one located next to all the warning lamp test switches in with the gearbox...
This could save you having to shut down again, swap the fuse, and start up again.. and at £3+VAT a minute......
