What has always worked for me are plain old kitchen matches, in situation where it was really necessary. That was because a lot of these situations occurred years ago, when matches was all I had. I now carry redundant items - usually a Bic lighter or equivalent, matches, and some kind of metal match/sparker, along with tinder, Esbit, and a small bottle of hand sanitizer, which lights quite readily(65% alcohol). I also tend to sprinkle mini-Bics throughout my packs and bags. Nowadays if I am planning for an overnight, I almost always carry some sort of a stove, usually a MSR Pocket Rocket and canister, along with a small cook kit, which usually has its own lighter.

The ability to start a fire has been absolutely critical for me on about ten occasions. I have been able to make or find shelter when necessary, but having guaranteed fire makers on my person has guaranteed a survivable night.

There are, however, times, at least here in the Southwest, when under no circumstances should one even think about starting a fire, not even a stove. Those, conveniently, are conditions when it is so hot and dry that a fire isn't vital. When conditions are that extreme, it is also a good idea to defer your trip until it rains.

It goes without saying that you need to perfect the skill of making fire before it gets critical. I am definitely rusty, compared to the past, partly because I usually have something in the way of fire starter or stove which makes it easy.