Given the choice between two functionally correct data structures with different performance profiles, you should pick the one more appropriate to the task at h

Given the choice between two functionally correct data structures with different performance profiles, you should pick the one more appropriate to the task at hand. A lot of performance issues can be proactively avoided with a bit of analytical thinking, but you do need to know how your data structures work and what their trade-offs are. Profilers are wonderful tools, but in the 15 years I've been professionally writing software the number of people I know that have ever used one numbers in the low 10s. Of those, the number that can derive meaningful data from a profile is even smaller. And finally, those that can spot "death from a thousand cuts" situations (quite common) from the proverbial method that takes 20% of all CPU time is even smaller yet. Profiling has a place, of course. But it's tricky to get right, incredibly time consuming without sampling, and often doesn't give you a complete picture. It's the performance equivalent of a debugger and really should be a fallback, not the only tool in your arsenal.