wow these forums' quote limitations tho
This guide may work on old (quite old) maps that are genuinely mistimed, but most of the time (especially on maps past 2011) you're actually just hitting too late or too early. Woobowiz is correct: mistimed maps are unrankable now, even if they're noticably off by just a couple of milliseconds. Changing offset based off of your own hit 'offset' rather than the map's timing, making the map's offset actually off and mistimed, will actually screw up your sense of rhythm further if you do it for most of your maps, and you'll end up deterring your accuracy in the future because you won't know how to time hits worth crap.
My point is is that if you hit too early or too late on certain maps and you change the offset when it's already correct, you'll just be setting yourself up for failure because you'll learn how to get good accuracy by hitting too early or too late (not by actually timing properly). If you do this too often, your accuracy will actually be pretty bad since you will never push yourself to learn how to time your hits properly--which is what accuracy is all about.
Mistimed maps are out there, I will admit, but I don't think there are as many as you say because of the current ranking criteria. I'm not saying never change the local offset, but what I am saying is always check whether a map is mistimed or you're mistiming the map before changing the local offset. Most of the time it will be the latter (unless you're retro and you exclusively play maps from 2008), which is why this is damaging for accuracy.
Mathsma wrote:You're missing the point. There are an incredible amount of songs that are incorrectly timed, he is saying you can fix that by changing your local offset.
Also sorry for lengthy explanation, but really felt like I had to shed some light on why this is a bad idea.
TL;DR: check a map's timing before screwing with the offset.