I'm just South of 40 and always try to live within my means. I say "try" because there is the rare exception when I spoil my kids or wife. However, I do my best to live the words carved by my school's founder:
I'm amazed at how many people don't follow this simple, yet basic rule. A neighbor of ours just lost his job. He's a great guy, has a wife and 2 kids that my kids play with all the time. I feel bad he was laid off, but you could see the writing on the wall that his position would not last. He had left a stable position in a stable (for this economy) industry in pursuit of greener pastures in the pre-fab home industry (yes, in the middle of the real estate crash). What was the first thing he did - bought a bigger boat. Now he's scrambling to make ends meet, but they have yet to put the boat up for sale.
I experience similar actions through my wife's friends. They're always running off to here or there, buying this or that. It's a little tough on my wife, since she can't join most of their girls nights out. They have no problem buying multiple bottles of $100+ wine. I know their husbands make more than me, but not to the extent that there should be such a difference in our ability to "consume." My wife finally found out they all just float it on credit cards. They're carrying balances of $10k or more!
You're on the right path. It's hard not to stray, when so many others seem to be getting along just fine with their lavish spending. However, if they die tomorrow, their kids will have nothing but a pile of debt to remind them of the good times.