I wouldn't say I was super frugal when I was younger, but I did know about getting good value out of things. Was happy to spend more if I felt it was a something that would last a good deal of time. I was also always good with numbers and saw how my parents struggled on a tight budget (both had low-paying jobs), so it was natural to me to be wise with money. And as my other half grew up in a relatively well off family, it's probably for the best for me to be dealing with all the finances!
However I will say that my "rules" (if I really have any) have certainly relaxed since paying off the mortgage early. Would love to say it was due to my prudence and financial skills, but it was really 99% luck. I don't think even a genius could have forseen that taking out a tracker mortgage that allowed unlimited overpayments a few years before a worldwide financial collapse that brought your interest rate to 0.5% for the next 12 straight years was going to happen! I carried on paying the £650 a month that was originally required even though the bank only wanted about £200pm.
But as soon as it was paid off and we now had that extra disposable money every month, it was a lot easier to be a little more carefree with spending - no big purchases, but certainly things like buying lunch every day when in the office instead of taking in a home-made sandwich, a few extra little treats here and there, upgrading to the next level of things you'd get the basic ones before, etc. Then before you know it, you've gotten used to your "new" budget and are spending right up to it, so despite the extra cash, you're actually only saving exactly the same amount you were beforehand and it's surprisingly hard to cut back.
