Unfortunately, it's one my wife and I are having to practice a lot right now.
Study materials, certification exams, cleaning up old debts, and saving for down-payments are all really expensive things. What that means for us, is that we have to say no to a lot of things we'd really like to be doing.
Cable TV? No.
Netflix? Not any more.
A new video card for my desktop? No.
Cute new shoes for my wife? No. (unless she asks three times, then I'm powerless to resist)
A better air conditioner since it was almost 100⁰ today? Afraid not.
Dining out? No. (Except today. When the air is hotter than blood, you should get a free pass. We used our 99⁰ free pass today for Chinese food. Love that almond chicken....)
Now, I'll be the first to admit that we sometimes don't say 'no' to everything we should (for reference, see today's free pass to Chinese food) but then let's be honest, everybody has that problem occasionally. The important part is that you're deliberate about it, rather than walking around with a careful ide.....
LOOK!!!! A CHICKEN!!!!!
Sorry about that, got distracted. What I was saying, is that you're not walking around with a careful idea and plan, only to throw it out the window every time you're distracted by something shiney. It's been said before (although I'm probably butchering the quote right now) that
I want to buy upgrades for my computer and a new holster for my camera, but I also want to get my IT certifications and save up for a down payment on a house.
I want a huge bowl of ice cream, but I want to lose another 30 pounds.
Being a A Grown Up™ means setting aside some of the little things that are less important, especially if it means setting them aside short-term, to help reach the big and important goals like a house we could raise children in and certifications that will improve my career long term. It's not always easy, but it's almost always worth the reward.