Depends on how you drive it. There is one place everyone forgets about and that is the PCV system. Pull your throttle body and see if your intake is filmed with oil. If it is, and your engine runs strong, you probably have a little bit of oil bypassing the PCV orifice (which is under the valley cover). I don't know about cleaning the under valley cover PCV, but, you may end up replacing the cover, about $100 or so.
The Cats will keep you from seeing smoke, except at startup. If you see a puff of smoke at startup, then you may need new valve seals. The LS valve seals are very good, so unless you overheated the engine, they are likely OK. A lot of folks suspect rings or valve seals, but my bet is PCV.
If it is PCV-related, you shouldn't ignore it, the oil can mess up your cats. If PCV, a catch-can may help.