If you live in a newer home and don't have any of the other risk factors, than it isn't really necessary, but there can be hidden exposures. Perhaps the soil outside your home, an old toy, an occupation or hobby, etc (did you ever notice the warnings on Christmas trees and lights?).
My son had a touch of pica as a baby and eat anything he could get his hands on (a spec of dirt, string, paper..he even chewed a hole into his crib railing). Even the average house dust can have lead in an older home, so everything that went into his mouth had potential to have some lead on it. I caught my son chewing on a window sill a handful of times when he was a toddler. I would have to pick the paint and wood out of his mouth and we lived in an old home, so I knew he needed to be tested. It was very invasive -a real blood draw, which he never had before. He did test rather high, but no chelation therapy was ordered. We were required to re-test again in a few months, and at that point the levels were closer to where they should be.
They used to say anything under 10 was OK. I heard they are thinking of lowering that number to 5. My son's level was 17, and later dropped to 3. A neighbor of mine said her daughter tested a bit high too, so if you are in an older home (pre-1970s) it might be a good idea to test. Maybe they have a less invasive test, like a finger prick.