Please please PLEASE don't start this "I lived just fine without it, why does anybody else need it?" shit again. We get it, you're old fashioned. Some people like to move forward with the times.
Revolving accounts (aka credit cards) are the single biggest contributor to your credit history. Longstanding low balance revolving accounts go the longest way to prove you're fiscally responsible to lenders, and if you want a good deal on a mortgage or car loan you're a damn fool not to have at least a basic $500 limit credit card backing you up.
Plus, using a bank debit card for everything is DANGEROUS when your money is already tight. Some transactions (gas stations in particular, preordering stuff will do this too sometimes) freeze large quantities of your "credit" account for a short period before processing the actual total, and if your bank account drops below zero even for a second you're gonna get slammed with overdraft charges. Credit cards charge by the average monthly balance so it doesn't really affect them, since the average is only calculated once in the month based on the actual transaction record and not any immediate balance shifts.
But on the subject of credit cards...don't pay the balance to zero every month. Keep at least one card with about 25% of it's total balance, and just pay it down to exactly that amount. Keeping a balance means you'll pay a little bit of interest (not horrible though as long as you keep it low), meaning the bank is making money off of you, meaning they're more willing to give you a higher limit. Keeping the card paid off usually means you get overlooked for limit increases, which further handicaps your credit score a bit (but this is far, far, FAR less important than keeping your accounts in good standing and paying your bills down, all things considered).
XI Wiki


