Everything I have read tells me not to re-use the snap lids on my mason jars when canning. I do anyway. I figure, if they seal...they seal. I have never once had one fail to seal.
Is it just a myth to get us to spend more money on their products, or is there something else to consider than just a seal (or not).
If I had one that didn't seal, I would just put it in the fridge and eat it first.