Every situation is different. In some cases you could literally be just a few postage stamps away from raising your credit score 100+ points in a few short weeks. The reality is if you do nothing you'll stay right where you are.
Here's a realistic example to consider: Let's say it takes you 40 hours over the next 6 months to get your score up. That's 6 ½ hours a month, or about 90 minutes a week. Let's say by improving your credit score you save just 2% on a $200,000 home mortgage loan. That will save you about $100,000 over a 30-year term. You just made $2,500 an hour for your time. Let's take a smaller example... a new car. Let's say instead of a 10% APR you qualify at 2% on a $20,000 car. That would save you $4,450 over a 5 year period. You just made $111 an hour for your time. From these examples you can see that spending just a little time learning the credit repair process can easily result in your credit repair work being the HIGHEST PAID WORK YOU WILL EVER DO IN YOUR LIFETIME!