This year, we ended up spending a lot more than expected due to hidden and ever-increasing costs (around a sports event and had to use a specified travel agent who was worse than useless - and due to the appalling - and I mean appalling!!!! state of the actual site, we spent an additional €1k on just food and drink in the hotel next door so that we wouldn't go down with food poisoning properly). It probably cost us about €8k overall. But once in a lifetime trip halfway around the world.
The year before, roughly €3.5k (flight, car hire, holiday home and daily watersports), with maybe another €500 or so over the 2 weeks on food, drink and eating out.
The previous year, roughly €3k (ferry, petrol, CP chalet for a week, and 2 nights in a hotel en route home). Again, with money for food etc added on.
We could spend less than that or a lot more, based on household income figures. Theoretically, it works out between 2-5% of our gross income for the actual holiday costs, and then spending money and some extra clothes etc on top. But we also have a mortgage, and want to spend on everyday things so that life runs smoothly and also some luxuries, and put money away for rainy days and retirement. So we stay within what we think is reasonable, and go for holidays that we enjoy.
I've gone camping with DD (DH thinks he's too old for a tent - but I'm working on persuading him). And we very often go self catering, whether in this country, the UK or France. DH and I have done the "sun/beach" type resort holiday in the past, but it doesn't interest us. I want to go skiing again, and I'd love to do a walking holiday in the Alps or somewhere like that. So we stick to what we like.
And by doing SC, we can save quite a lot and then not feel the least guilty about getting lovely French cheeses and wines and breads and making that our dinner. Or eating out a few times a week while away (we tend to eat out once a day, eat in the accommodation once a day, and the 3rd meal might be a picnic, eat out or eat in depending on what we feel like or even skip a meal if we've had say a large breakfast and plan a large but early dinner. And I also don't feel guilty about getting easy to cook options - but there are usually such lovely, and such cheap, such options available especially in France, that it works out very economical as well as very nice and easy for holiday cooking).
And I also agree with things like using Avios points or airmiles towards car rental or flights or accommodation nights on the road. We save up any we get either through work or personal travel and spending, and make use of them towards family trips. It can also often mean we can upgrade a room or a car to be comfortable rather than just getting the lowest level that we can get away with.