Same here. Relatively poor upbringing. Father always had an old banger car that was forever breaking down, ice on inside of windows, wearing school uniform evenings & weekends because we had few other clothes to wear, riding around on a second hand child's bike as a teenager, never had any holidays, hit & miss whether we got much in the way of presents at Xmas and birthdays. At the time, we knew no different.
I was VERY careful with money in my part time jobs whilst at school and my first full time job. I'd squirrel money away - always had something to save up for. I got enormous pleasure out of buying things that had taken me weeks or months to save for. Far better feeling that just spending/wasting it on novelties/rubbish etc.
When I qualified and starting earning decent money, I simply didn't change. Still lived a very frugal/careful way of life, and the money just built up in the bank accounts. Then I was watching the interest grow (in the 80s when interest rates were a lot higher). Luckily, my boyfriend was exactly the same. We'd stay in with a takeaway and video rather than go out and spend £50 or so on drinks and a meal.
When it came to buying our first house, we'd managed to save half the asking price, so only needed a mortgage for the other half. By saving and being careful, we paid off the mortgage after only 10 years or so. Then we were back into "savings mode" and watching the bank balances build up again.
Over all that time, we were hardly paupers. We'd have 2 or 3 holidays each year (usually 1 or 2 were expensive, i.e. California, Kenya. Egypt, etc), the other(s) being skiing or golfing holidays. We'd also moved onto buying decent cars, including brand new occasionally (still saving before buying rather than getting HP, leases or loans for them). We'd also gone right through the house, replacing everything, kitchen, bathrooms, roof, boiler, rewiring, radiators, etc).
We're now approaching early retirement and are already working reduced hours. We don't have hundreds of thousands in savings, but we have enough and we've a couple of relatively modest private pensions. We'll be able to buy replacement cars as and when needed (not brand new but 3 years old or so each time). We'll have enough for house maintenance. We'll have enough for 1 or 2 holidays per year.
In our minds, we're "rich" in that we're comfortable but we don't have money to waste, we never have wasted money. Never bought gadgets, never bought designer clothes, never bought much jewellery, etc. Our house is "minimalistic" in looks, but that's because we really don't have much - no shelves full of books or CDs or DVDs (we sell on ebay once watched/read).
I'm literally checking bank accounts every few days, logging everything in a book-keeping package so we keep a close eye on spending and investments/savings etc. I've set up diary reminders for phone/utility/broadband/Sky contracts so that we don't end up stuck on expensive contracts/tarriffs.
Saving money rather than spending really is a state of mind. Our upbringings were very similar. Neither of our parents had lots of money, neither wasted money, all saved up before spending (except mortgage).
And it's not as if either of us have been really high earners. Neither of us have ever earned more than the higher rate tax threshold (currently £50k), not even at the heights of our careers. Our wages were more usually around average wage (currently £30k or so full time equivalent) but now a lot lower since we're part time.