Optimise only if needed; then only where needed. The JVM and also javascript engines have increased in performance markedly (clawing back a little of the perfo

Optimise only if needed; then only where needed. The JVM and also javascript engines have increased in performance markedly (clawing back a little of the performance they squandered in the first place...). Perhaps iOS is very performant - because it had to be, especially on the original iPhone.