Comment by spaghetti

Milestones are great. However I like to have reasonably consistent prices. For a $4000 project you can have, say, four milestones with prices $500, $1000, $1000, $1500. This way the client can bail out after the first milestone if things aren't going well. And they won't lose too much money. Also the client gets the "carrot on a stick" with the hefty fourth milestone without being obnoxious (with a $3200 fourth milestone for example).