To be quite honest?
We're both decent earners, AND low-ish spenders.
We didn't start out on high wages (£12k for him, £15k for me first year out of Uni. But being low spenders meant that we weren't inclined to be extravagent on those salaries.
Even once we'd moved to graduate jobs, we didn't spend a lot on:
Cars
Phones
TV/Internet packages (no Sky)
Clothes/hair and beauty
We have spent a reasonable amount on holidays and travel, but off peak, deals, clubcard points have gone a long way to keeping those cheap.
Now we're both the highest earners in our friend groups, and we still spend quite low on the above. I turn up to get togethers in the oldest car, no manicure, the cheapest phone (and it's cracked), and the handbag on my arm did not cost anywhere near the others.
I'm not bragging - it's just how we are. It means we can continue to afford most things thrown at us super easily. We are good at deferring pleasure, IN NO SMALL PART because if we do want something, we only need to snap our fingers (or one click on Amazon) to get it.
House - we saved around £75k between us over 8 years.
Wedding - we saved, and parents contributed. £13k wedding, £6k honeymoon. A lot to spend on one day? Sure, but I can't see myself regretting it. We had a great time and put on a great day for our friends.
Kids - we'll save £8k to support the year of split maternity/paternity leave (husband gets 4 months full pay).
Lucky? Yes.
Hard working? Yes.
Frugal? Yes.
Privileged? Yes.
Savvy? Yes.
All these things combined contribute to an extremely fortunate position.