If a child has genuinely never had a punishment at home for bad behaviour, how do they cope when they come up against punishment for bad behaviour outside the home? For example, if they are given a detention or a punishment exercise at school, or a fine by the courts.
Like Bertie, I use a mixture of techniques - what Morloth describes as the 'What works' approach. Fwiw, I am pretty sure that setting boundaries and explaining why the child shouldn't have crossed them, would not have worked with my boys (and I freely confess to being jealous that Tortoise's dc responds so well to this).
I did find that it got harder as the boys got older - because they were out of my supervision more and could get led into bad behaviour, as happened with ds1 when a friend he was with regularly nicked sweets from the corner shop - ds1 (12) decided to have a go, and got caught. He was horrified and appalled at what he'd done, wrote a letter of apology to the shop and took it straight in - we only found out about this when we got a letter from the school (the shopkeeper had reported him to the school, as he was in uniform and on his way there when it happened). The school punished him, and so did we - I don't think we could have not punished him in that circumstance.
I do think that there is worse mischief/bad behaviour that they can get up to as they get older and are more independant, and some of these things can't be dealt with other than with a punishment, imo. Things we've had to deal with recently include coming hope at 11.15pm after going out for the afternoon with friends (ds2, 16), stealing money from my purse, riding a friend's unlicensed, untaxed motorbike in the woods (also ds2 - this incident used by him as evidence of how mature they were because they were wearing helmets and gauntlets and only riding slowly - and therefore we were being unreasonable to object to him being out until 11.15 - sigh), and utter melt-downs from ds3 (14) over such parental cruelty as insisting he walks the dog or tidies his room - he has problems with his temper, and would lose it entirely with me (swearing at me and calling me all sorts of unacceptable names) - though this is getting better now, because we cracked down on it firmly.
Reading back the last couple of paragraphs, it sounds as if I am an entirely crap mother - that's not the point I was trying to make, honest! By and large the boys are pretty good - responsible, polite to other adults, kind, and doing well at school, but even the best teenagers can completely blindside you with something you were not expecting them to do - and you have to have something in your arsenal to deal with that.