The system and maths boys here are perhaps looking into the wrong envelope on this [their own]. Nothing wrong with that as we all tend to see the world through our own glasses, but it might be missing TheEasyRun's point on staking completely. Hopefully he'll get to a couple of examples to clarify what in some peoples books, can't work.

I don't bet a set % of bank and mostly never have and I'm sure their are plenty of other punters who don't either. I bet mostly flat stakes to win [a bit of place too] but as to staking amount or % of bank it's a [rough] sliding scale depending on the odds and what exposure to loss I feel the bet has.

Generally the average punter bets the largest amounts on the smallest odds and the smallest amount on the largest odds. To many punters that is just crazy as then odds alone are being used as a risk assessment [the punter has no faith in their own assessment ability] and that leads to confusion about SP odds and true odds and also the smallest returns from the best overlay opportunities.

I had three bets yesterday, all with differing odds and exposure to loss based on my own personal judgement. My largest bet [Campeche] paid 4/1 and my smallest [On Bail] paid just over evens. My middling bet [Beautiful Dragon] started at 6/1 and lost. My evens bet was the smallest because it had the least overlay value even though I gave it the best chance of winning. The middle size bet I felt had the most loss exposure, but it was the largest bet in my opinion that has the best value. However, it could have been the 6/1 bet with the largest bet amount if I had felt differently about it's exposure to loss.
Looking at it in pot terms, my profit for the year is running at about 35%, but if all bets had been the same size % of my bank, the profit would be about 20% pot. I'm sure there are much better punters out there than I am.

I'm sure there are plenty of other punter with a similar staking outlook to myself and sitting down with a calculator and working out what is and isn't possible, just never enters our radar. We just bet and keep tabs on progress [or lack there of] and our noses to the ground looking for good bets, not better staking theories of what's possible and what isn't.