Credit is justifyable for buying houses. Credit cards to finance virtually everything else in life is a mistake that the credit card company's work very hard to convince us is the approach that financially successful people pursue. The most financially successful people in this country are the least apt to use credit cards to make purchases, virtually all purchases, according to recent studies.
Thanks to the CC industry, the least well off and least capable of controlling their financial condition are the people most apt to use credit cards according to the most current studies.
You would be very surprised how much ones' disposable income increases when they no longer have financed purchases to pay for each month. My wife is a shopper (we probably donate 10 Coach purses a year to Goodwill), big time and used to have multiple credit cards, many of which I was not aware of. A while back, we decided (at my urging) that from that point forward, we would keep one credit card (for rental cars, etc. . .) and everything else would be paid with cash (check or debit card). We worked on paying off anything purchased through financing (cars, boat, cc, furniture, etc. . . and paid it off as fast as we could). We now have a mortgage, which we pay monthly along with an additional overage of the monthly mortgage amount (doing this cuts 3 years of the remaining 8 years left on our 15 yr. mortgage and saves us $40,000 in finance charges). We both now maximize our 401Ks, increased savings for our kids college funds and have so much money going into savings accounts that we now have a system with multiple accounts and an automatic transfer system when one account reaches a certain limit money gets transfered out to the other account, taking the first account back down to $5k. When the second account reaches a certain limit, money gets transferred into various investments (IRAs, additional funds in 529bs, etc. . . ).
My wife is now amazed at how much more money we have (and we are saving at a much, much higher rate) and we are freer to buy things we want, and we have both become more aware of what we really want vs. just impulse buying as it is being done with cash.
I will never finance another car, boat, trip, home improvement, etc. . . It is just too easy to save when so much money is not already spent before the month already starts. It also helps teach the kids a much better way to manage money.
If you can't afford to pay cash for those new speakers . . . . . you can't afford those new speakers!