How to tell if termites exist?

What are some tell tale signs if a property may has termites. especially in the winter when the “mud trails” may not be as visible? Also, is it wise to attempt to have a property treated and rehabbed if termites exist or does it usually cost more than the effort is worth?

Have it inspected by a professional. They will usually do it for a small sum in hopes they can sell you a treatment. If they find signs you would fix any damage. Now what if you also treated it yourself with baits while you rehabbed. Would the tunnels still be there after they were identified? Would an inspector find an active or signs of a precious infestation?