Oh dear. I've been wasting time.
Credit Cards don't help you get mortgages, in fact they can hurt you! If you have a credit card with open credit on it, the bank assumes that you will charge it up to the max (because guess what, MOST FOLKS DO.. they get a house and then go buy drapes, furniture etc etc etc to fill that new house and they do it on credit!) So large open balances on unsecured lines of credit can be a hinderence to finding a mortgage.
If you are currently living your life with no debt, I definately would like to A) give you Kudos, you are living on less than you make which is better than most of the american public! If you are doing this and saving for your retirement you are doing better than 95% of the american public... if you are doing this and you have a retirement savings of over 100k currently you are doing better than 99% of the american public!
Stay away from debt as much as you can... Yes I understand a mortgage may be needed to get a home, and that's fine... but please don't fall into the trap of consumer credit, or that you need credit cards etc to get a mortgage.
You should avoid debt as much as possible in your life.
(Yes some will make arguments about using debt to build wealth... that's an ENTIRELY different situation that 99.99% of people use debt for.. so please don't fall into the trap... you are not creating wealth buying big screen tv's on credit cards... unless you have a plan to sell them immediately for more than you paid for them).