If you have wood above concrete this can be hard to avoid entirely, and outdoors even a metal bracket can collect water.
Wood is not a sponge. It’s a directional sponge. Water wicks from the end much faster (farther) than the sides. Some of the best deck designs carry the cross beams directly on the supports, which means no end grain sits where water can collect. The wooden sill on a concrete foundation you can’t usually avoid, but the fact that the wood is lengthwise is, I suspect, the only reason we get away with it. It provides a little protection, but I think code most places may be pressure treated lumber for that as well, since a 50+ year house can still end up needing the sills replaced otherwise.
Never let dirt touch your siding, and never slope your landscaping toward the house.
Termites really love wet wood.