Just to be clear I am looking at the last week or two and using that to make an educated guess at a likely low that will be hit in the near future (next week or two) due to normal fluctuation and then placing a limit order for that amount, not waiting for a 'major correction' or sitting around checking the current price all day long. Just rough back of the envelope numbers show doing it this way has saved a few hundreds bucks versus buying at the average price during that time.
I don't think that falls under what most people mean when they say "market timing", but I could be wrong.
The risk is that you don't hit the price you're looking for because the market goes up say 5% during the couple weeks you're waiting (and doesn't come back down before you adjust your price upwards). Then you lose quite a bit of gain. I don't know how often those larger loses will happen compared to the very small gains you get by playing the price target game. Maybe it's a wash. Who knows? If you're having fun, and make sure you keep investing continually, it's probably cheap fun.
Mathematically, the expected value of waiting is negative. If you expect the product to go up in the long term (which you should if you're buying it), then it necessarily follows that the product will (on average) go up in the short term. Of course it won't every time since markets follow "random walks", but in aggregate, it will go up. You can even calculate it, if it goes up 6% a year, then waiting a half a year will be ~3%, waiting a week will be ~.115% (roughly, due to compounding). This is, of course, looking at expected value, the variance is high.
To reconcile this with how "easy" it is to wait for a dip, is you are only gaining a small amount from waiting for a dip, but it's a large loss if you missed a long-term low, as forummm describes. In aggregate, of course, it's a small loss.