Sure I'll throw in my 10c, I don't need a second invitation to talk about risk and position sizing.
So firstly yes I think you should eventually pick your own percent that matches your strategy, style & ultimately what you are trading, the exact one is arbitrary... to an extent (where 100% is betting everything on black and the casino, and 0% is putting your cash under the bed and never doing anything with it, there's probably a sensible middle ground), but you'd probably need a fair amount of trading under your belt to know the sort of numbers that work best for you.
When I think about "risking 10% per trade" for example, I don't think "you can only use 10% of the 100k account on any trade", it would be "the lowest you can set a stop-loss, is a 10% loss to your account". It this regard, the number I think I normally hear is more like 1% risk per trade, so on a 100k account you would not set your stop lower than a 1k loss. So let's say you had 10k parcel on stock xyz at 10c, your stop could not be any lower than 9c, or you would have to lower your position size. If you threw everything in like a madman, with all 100k your stop would need to be equally silly at 9.9c. On a 5k parcel it could be no lower than 8c etc. That's how I understand it and is a pretty rudimentary explanation of position sizing and risk quantifying. The smaller your position size, the more leeway you have on a per-trade basis and the more risk you can allow yourself.
Of course technically you are risking everything then you buy a stock as anything can go to 0 after just being suspended with you trapped in it, but that's a different element of risk that is always present. That's probably one aside from the risk I'm talking about that should always be kept in mind, even if you stategy say I can put it all on 10c and a stop at 9.9c, common sense says that's a bad idea.
Risk management doesn't stop anyone from being a terrible trader, but it should keep you alive much longer than without anything, in fact it would take quite some time to blow up your account if you kept to the 1% rule, I think cabbie or someone posted something a while back that showed just how long that would take. Certainly enough time for most to figure out what they are doing, or that they aren't cut out for it.
On smaller accounts, the 1% rule may be too strict. Let's say you are playing with 5k, that's a $50 maximum loss you are setting yourself per trade. So lets say you want to set a 9c stop loss on xyz, you'd need to have no lager than a $500 parcel. Depending on your brokerage costs, you'd be making things very tough on yourself trying to turn a profit on those numbers, and maybe a 2% risk per trade would be better if the brokerage is hitting your risk/reward too much that you can't make any trades. Or maybe you are someone that only takes very few but which are much better risk/reward, so your allowed risk needs to be higher rate so you can earn more on fewer trades. Let's say you ramp that up to a 3% risk allowed, put your stop at 9.5c this time from a 10c buy, you can risk $150 per trade, or $30 per pip, so that's 3k you could put into the trade. Small changes to the numbers can make a big difference. If you were making a lot of trades a day with small brokerage on a large account you may set it lower like 0.5%
And of course you'd be using your TA (or FA) to determine where you think the price support is (or whatever black magic you use to judge a trade), and you'd be plonking your stop there and then adjusting the position size, not the other way around.
Hopefully that all makes sense, maybe getting a bit too dense with the numbers. I don't think I've heard too many talk much about risk management this way on HC, so hopefully some find it interesting and is some food for thought. It can be a decent way to bring about some consistency and order to the way you trade.
Cheers.
