You're not going to chase down the gazelle by walking.

(Sorry, I really like doing analogy analysis for the lulz.)

While that analogy is absolutely true, the amount of prep work (stalking) that goes into that final sprint is super important. Personally, I have no problems with "move fast; break things" unless there isn't an actual direction plotted first. Redundancy can even be implemented quickly, like when animals hunt it packs.

Failure is always an option, but always double the estimated time it takes to do a change of only to account for any unknowns.