On the firewood tools, not only have them but know how to use them, and how to maintain them. No use having a sledge and maul if you have a heart attack the first time you try using them, or miss with that axe and dump it into your shin, or find out you only have the stamina to do two cuts with that big-ass crosscut saw.
And chainsaws? If a fully stocked and functional ER isn’t within reasonable reach, stay the heck away from them unless you have full kevlar chaps, gloves, helmet, and faceplate. The other tools can kill you if you work at it, but the chainsaw has a lethal mind of its own.
Then there’s maintenance. Saw files, axe stones, file sets, saw clamps or the materials and ability to build them. This shit doesn’t go well when your tools are dull and rusted.
The time to train up on all this is every fall and winter.