I've mostly got away with it in the past - it's survived much heavier hackernewsings - but I think I installed a plugin recently that was rather more costly than it should have been, and then the fact that I hadn't previously looked under the hood bit me.

Edit: It's also worth noting I don't think principle 1 is always a good idea. This advice is very specifically optimised for the case of joining an existing company with an existing product and an existing team. If you're starting from scratch you should do more up front investigation and thinking things through. though maybe not orders of magnitude more.

Instead I flailed around blindly in the usual manner of trying to get PHP applications to work and seem to have fixed the problem. :-)

I should really move my blog to an environment I actually understand and have control over.