ashber, welcome to the forum!
HTSU is right on the money, as usual. I'd like to add another perspective to all this.
I don't want to be a downer, but should a divorce occur, or should your spouse pass away, you definitely DO NOT want to be left without any credit in your own name! You've got to keep some good credit history for yourself, no matter what...and I mean, JUST yourself alone on that credit.
Should the unexpected actually happen, then at least your financial life won't be as stressful, and you'll have some options.
Just my 2 cents worth.
Edited for typo...
Do not cancel all of your cards, especially your oldes. If you had 12 cards all with high AF's, then you decide where to prune.
But just because you have credit does not prevent you from using cash from now on. If you are a bit of a credit addict and tend to spend where you shouldn't, then DO NOT carry the cards with you. Put them in a shoe box in the closet, in your safe, in your sock drawer.
You do need to exercise them every couple months. My opinion: put your phone, internet, cable on auto draft across a few of them and just PIF each month like they were debit cards.
Buy something occassionally on the store cards. Wait till the "after Christmas" or liquidation sales so that you can buy actual values. Usually you can buy online so that you don't even have to go to the store. Store cards do not have to be used nearly as often as the majors to keep healthy.
You are correct that you will need established credit when you buy a home. So, if you choose to prune back a couple cards, try not to do so with the oldest 1 or 2. The more "old" accounts you have, the less impact that new loans or accounts down the road will affect your AAoA. You want to maintain an AAoA of at least 6 years if possible. And when you get married, you will get a home mortgage, probably a car loan, etc.
Don't be afraid of credit, just use it wisely, use it as a debit card and convenience card and credit reference.
I don't want to be a downer, but should a divorce occur, or should your spouse pass away, you definitely DO NOT want to be left without any credit in your own name!
I also agree 100%. DW has her own credit in case something happens to me.