Tim Inman: I think that universally about 40 percent relative humidity is ideal for most furniture and wood environments. Try to maintain this all year around. Another way to express this would be simply to say that the humidity in your basement workshop should be the same as the humidity in the upstairs or in your office where your nice custom-made heirloom furniture will live its life - until your kids fight over who gets it when you're done and gone.

Chris Marshall: For those of you with dehumidifiers that don't provide a readout showing relative humidity -- mine doesn't -- buy a hygrometer and put it up in the shop. They're one of the features that are often included on indoor/outdoor digital thermometers with a clock. Inexpensive and very handy.