I became real good at managing my credit score 30 years ago, and have just been too lazy to write it up. There is a fairly good article at Dolans.com to get you there if you don’t know how.
How is this cheap lazy investing? First, there are lots of companies that will charge you from $5 – $5,000 to do what you can do for free. And if you have ever tried doing much of anything with a bad credit rating, you know it is hard. It is less work to maintain good credit than to re-establish it, and still less work to re-establish knowing what to do than guessing.