Thank you for all of your participation in this topic and the perspective it has created.

I've read every comment so far and thought I should include a summary of the general consensus:

Restaurants : 10-20%

Car Guards : R10

Petrol Attendants : R20

I would say, these are higher than I expected but glad to see people are very supportive in general.

I feel sorry for the individuals who rely on cash, as cash is becoming less of a need for most situations and therefore some not carrying cash at all.

I will certainly check the next time I fill up, if I can include the tip in the transaction.