Its not a matter of being rich, but a matter of "Which is more valuable/important to me at the moment, £10 or 2 hours of my time?" Sometimes its £10, sometimes its 2 hours.
If I found my room rent for uni has increased by £10 from the previous term then I'd just write the cheque and not think about it, the overall increase isn't much. If I was in a store and the person at the checkout asked for £10 more than my items should be, I'd ask them if they're sure about the total (though rare to happen since its all done by the computer).
If it was quick and easy to sort out a problem like that, I'd do it. If it only takes your dad 15 minutes to sort his cable bill, then do it.