Yep. The problem is that while a stop loss sounds sensible, it...

Yep. The problem is that while a stop loss sounds sensible, it has a cost. The cost of a stop loss is essentially a function of the volatility of the asset (in much the same way that the cost of a put). The difference between a put and a stop loss though, is that whereas a put has an explicit premium and no gap risk, the cost of a stop loss only realised as a intermittent volatility triggers you out at low prices (and then perhaps in again at higher prices if you still believe the fundamentals). You could limit this cost by trading out on the upside too, but net, net you'll just end up paying away tx costs and tax.

The problem of stop losses is probably exacerbated most in stocks like VLA where the price often changes significantly on no news....which is a fairly clear amplification of an at least partial stochastic process that by definition we can have no insight on. Take the "dump" that has been discussed on this thread for example: if true, the impact of the dump is not related to fundamentals, yet might have had a marked impact on the stock price. Is it really sensible to sell into that, especially if your long term aim is to remain exposed to the fundamentals that you bought in on?

My advice to myself is to always limit exposure to speculative stocks - no matter how compelling - to an amount I am prepared to write off. That way I don't give a flick about the price, so long as the fundamentals remain intact. This strategy has thus far served me well.