You should expect that over the long term, your losses will equal the house edge. The more you play, the more your losses will approach that of the house edge.

You should expect that over the long term, your losses will equal the house edge. The more you play, the more your losses will approach that of the house edge. In the short term, you'll see lots of variance. So, the answer to your question is that you should never start. There is never a good time to start. And there's no betting system which gets you over the house edge.