When my wife and I first really got settled down (house, first kid, etc) about 6 years ago, I'd just moved to the area about a year before, and taken a bit of a paycut to get into my field in this area - I work in a pretty specialized field where there will typically be only 2 or 3 employers per major city (we live near Dallas), except for LA which has many. The money certainly wasn't terrible, but it was a bit tight. In a typical month, we'd be able to save about 400.00 in those days.
In those days, we saved what we could because we saw it as layers of protection between our nice little life and things going wrong. Of course, we still see it that way, but we were very accutely aware of it then because we hadn't set our roots very deep yet.
Anyway, I really carved out a niche for the company I worked for then (and still do), which was also going through some explosive growth. So the raises were fairly spectacular. 15k one year, then 20 the next, then another 10, then a whopping 27.5. The worst year was 7.5 which was last year. The end result was about 125% pay raise over 5 years. During all of this, there was a bit of a sense of "knock on wood, this seems to be working", but each time I got one of those raises, neither of us really felt any need to trade up some aspect of our lives. We liked our life, and didn't see any need to change it with a bigger house more befitting of our income, a really nice car (though I still spray drool over any corvette that I get with 50 feet of!), or any of that. So, despite all of those raises (which have not come without a cost - work responsibility/stress have increased to a point where I don't really enjoy work anymore, which is a real shame because I used to love it), we're still living more or less the same way we were 5 years ago, with maybe just a bit of creep along the way, but not much. That's how we've managed to live below our means and save quite a bit - just working hard, and when the raises come, resisting any temptation to trade up in our expenses. We do treat ourselves, but the golden rule is that we're only allowed to blow lump sums, not add new monthly commitments.