I'm probably thinking of algos more generally and generically. For example, whatever the class of trades, I think that what you are doing is making a stochastic forecast of future price movements. So maybe there's a good separation possible between your algorithms that create a distribution and algos that determine how to trade once you have that distribution. But saying this probably reveals a bias I have to think statistically. And I totally agree the majority of the system build thats important is the boring stuff. An algorithm should be able to tell if the market feed has died or the market shuts down unexpectedly, right? And know what to do next. And good to hear that someone thinks the costs are much less than popular opinion suggests.