I'd say three months is fairly consistent, but honestly anyone's opinion of a timeframe before one can be called consistent is just that, an opinion.
Anyway, my input on this thread is mostly just this. In the last couple weeks, I have made more money in positions I held overnight than I have in positions I left intraday.
I realize a lot of this is due to limitation of not being a qualified pattern day trader and need to limit my intraday trades to 3 per 5 day period. I therefore need to seek best entry positions, and those tend to carry me overnight.
Once I break $25,000 in my account, I am sure my opinion will change, however I have always envisioned being a hybrid day trader/swing trader since I started this venture.
So far, I have gained 30% in since two monday's ago, so I don't think that's so bad for someone who isn't allowed to day trade yet.