First of all, diversification, not all eggs in one basket, that way the hit, whatever it may be, won't get you out of business.
Also dont forget gaps can happen against or in your favor, so mathematically speaking they balance out.
Average up only works when you think the next big move is with extreme momentum, otherwise it can hurt you, many times quite badly. And if you knew, you would go all in from the start, but then again you never know.
It is easy to analyze good price action after the fact, it already happened, has very little chance of going nowhere, cause we already know it was a trend.
Newbies say wow, we old timers know the fairy tale already.
Choose a horizontal line that matters, choose wisely.
Above it bullish, below it bearish.
The farther you initiate from this line, the bigger your stop will be.
Trends are bullshit, they only exist after the fact.