I absolutely love this question. It's a question everyone should...

I absolutely love this question. It's a question everyone should ask themselves. If you come up with any kind of number, then you are a trader. The good kinds of traders know what they do and have timeframes and a strategy. The other kind are those who think they are investing. As others have said, for FA investors, there isn't a price to sell at as long as the fundamentals haven't changed.

BUT what a significant drop in price would result in a massive time investment digging even deeper and checking news etc. trying to find if my investment case was wrong. If I did miss something, I re-evaluate and possibly sell. If nothing has changed, then it's a hold, because I could still be missing something and not know it. If I am confident other market participants have messed up, then it's a bargain and time to buy even more if it suits your diversification targets.

In the current case, it's looking like a bargain. Unfortunately I'm no good at TA so I wouldn't be able to pick the cheapest entry and will have to settle for knowing I got my money's worth anyway.