Insure that any Ethernet/Cat-5e or 6 cable you install, especially for POE, is solid (not stranded) copper (not CCA/Copper Clad Aluminum).
Many pre-terminated cables available from Internet merchants (even Amazon) are CCA so ask if it's not stated. CCA cable will not have a UL-certification so if its states that it does or the UL logo appears on any CAT cable that is CCA then it is counterfeit.
An important reason to use only cable that can obtain a UL-listing is so that its jacket is flame tested to not assist with spreading a fire, even from another source, between floor or rooms.
Insure the cable's jacket is rated for the application: CMR jacket for "Riser" or CMP for "Plenum". CMP can be used where CMR is suitable but not the other way around (CMR can not be used where CMP is required). CMR is likely the most used and the cheapest, it's for use in walls, between floors, in attics and in crawl spaces. It should not be directly exposed to sunlight and the elements in general, as it will work for some time but will deteriorate sooner since the jacket is not rated for that application.
There are also UV-rated jackets for outdoor and jackets for direct-burial or flooded burial.