Caulking and paint need yearly maintenance to ensure that it is still protecting your house. A common spot to find hidden damage is at exposed wood trim, especially at areas that have a latex caulk sealing a gap. Caulking with a coat of paint is pretty good protection for wood, but once it fails water has an easy path to wood and can cause hidden damage.
Just a little bit of probing at a bubbling area reveals hidden damage. I used fairly light pressure here and the knife slid right in to the wood. You can see the hidden rot underneath. This has been going on for a while. It's likely that the previous homeowner painted over a failing area of paint without fixing the underlying damage.
Brian Jovag, owner of Jovag Home Inspection.