Is there a way to know how many spendable merits are going to expire soon ? If not, it should be included in profile if possible.
Sendable merit or aka sMerit is not expired, not decayed with time, at least now. In future, it can be decayed or expired if theymos changes his mind.
@OP account was from before the merit system was created, so he may got an airdrop sMerit. I don't know if he got those sMerits or if his rank was too low to get an airdrop sMerit, but in any case, until now, this airdrop sMerit has not decayed with time. This may happen in the future, it may not happen, so you should spend it on high-quality posts, as keeping them is worthless.