Aahh, the 'standard overhead join'! If only it was 'standard'. Some airfields seem to have developed their own joining patterns, no doubt for good reason (gliders, helos, parachutes, local noise, etc.)
Depends a bit on the level of the local Air Traffic Service and the availability of radio. If in doubt, I ask what they would like me to do. If there's no-one around, I check the signal square (if there is one) and join overhead.
If you make contact early enough, it's not normally a problem to arrange a straight-in, base leg or downwind join.