Yesterday, I met a lady who was telling me about a course she took in gardening. The woman teaching it was a "nut on soil," she claimed. Actually, I guess I have to agree, because she said the way this lady dealt with poor soil was to REPLACE it!!!! YIKES!
You don't have to replace your soil in order to have it be adequate for your plants! You may certainly have to AMEND it, however!
The first thing that should pop into your mind are the words, "SOIL TEST"! Call your Extension Service at the local Land Grant College (or University). They will be able to accomodate you, or tell you what to do in order to get your soil tested.
You send them a sample of the soil with a description of what you intend to grow in that soil, whether it be lawn, perennials, blueberries or mountain laurel. They'll tell you what you need to do to make that soil good for your intended use.
Every garden should have a compost bin. The first thing you should add to every planting hole is some well rotted compost. It's a wonderful amendment to ANY soil!