A couple easy field tests from an old wood burner:
Knock a couple splits together. Wet wood thumps, dry wood rings.
If you throw a split on hot coals and it immediately bursts into bright flames, at least the outside is dry. If it sits there and hisses at you, it's pretty wet.
If you split a split and the fresh-split face is a darker color than the old face, it's wet inside.
Honestly 90% of the problems people ask about here boil down to 'wet wood', but a lot of people aren't open to hearing that answer.
There's been a couple that I remember in particular who had long, long threads detailing their trying journey troubleshooting the elusive manufacturing defect in their first stove, ignoring everyone who said it was their wood or their venting, and then they replaced the bad stove and somehow amazingly got a different stove from a different manufacturer which mysteriously had the same exact problem.... what are the odds...