1. Unnecessary Purchases
More than once, you've found yourself having to buy a replacement simply because you lost the first item.
You know you have some phone chargers, but who knows where any are. You just keeping buying new ones. You also know you had an awesome gift stashed away for your brother's birthday, one you snapped up three months ago because you knew he'd love it. You just can't remember where you stored it, and his birthday's fast approaching, so you'll just have to buy a gift card.
Solution: Purge clutter and institute organizational systems for the things you do keep. You'll find your belongings easily when they're not buried under a heap of clutter, and if you always keep things in designated spaces, you'll know right where they are when you need them. Devote 10 minutes every night to putting things back where they belong.
2. Shopping Gone Wild
Shopping trips are normally a guessing game for you because you keep forgetting to mark down items when you run out of them, or you're so rushed you never have time to put together a shopping list.
Instead, you grab things willy-nilly, buying tons of stuff you don't need because you're not sure if you're out of it -- while simultaneously managing to miss several key things (like toilet paper) that you desperately require.
Solution: Write everything down. When you're low on a household item (don't wait till you're out completely), put it down on your shopping list. When you're about to head to the store, inventory what you'll need for the upcoming week (or weeks) and add it to the list. Never shop without a plan.
It may take a few extra minutes, but it will be worth it when you don't have to rush out at 2 a.m. for that unfortunately forgotten TP.
3. Late Fees
You're not paying late fees because you don't have enough money. You're paying late fees because you just never get around to mailing the checks.
You don't know where half your bills wound up, anyway, and it seems impossible to track all those different due dates. Sure, you had the money in your account. You could have paid on time. But who can keep track of everything?
Solution: Set it and forget it. Set up automated payments directly from your checking account so you'll never miss a deadline again. No need to track which accounts you need to log onto when, or running to the post office hoping your check will go out in time. Your bills we be paid by due date every month, and you won't need to worry about it.
4. Vanishing Money
Your friend gave you a $20 for the meal you covered last time you hung out, and you put it ... somewhere. When it emerges from the piles in your apartment, it will be a nice surprise.
Whether it's literal money (as in dollars and cents) or money you aren't claiming (uncashed checks, rebate forms you haven't submitted), your forgetfulness is costing you big time.
Solution: Whenever you have cash (or checks or rebates) in hand, observe the "only touch it once" rule. That instant that paper is in your hot little hands do with it whatever you need to do. Deposit it, put it in your wallet or stick a stamp on it and mail it out.
Setting things down somewhere (and maybe forgetting where) does not work well. Take care of it now and save yourself the hassle.