A little is too much
Have you ever looked under you sink and noticed a little bit of moisture and assumed "no big deal". Nothing could be more false. Moisture under a sink could be a ton of different issues, from a slow drip from the faucet supply, to a slow drip from your drain. Either case is bad, but from the drain, you're actually dumping unsanitary water, drip by drip, into the wood of your cabinet, harboring mold and mildew.
A little water is not just a little problem. The plumbing in your home needs to be tight. Tight enough to not allow any water to escape from it. Small issues will always turn into larger and more expensive ones, so call your service professional to come take a look. It doesn't hurt to check on it and is most likely saving you a ton of headaches and money in the long haul.