Carpet beetles are normally less than half an inch long and infest carpets inside homes. They are known for eating keratin, which is a fibrous protein found inside many clothing items and carpets. Because of this before they are seen an infestation of carpet beetles sometimes looks like infestations of moths. While they are found in fabrics they can also be found in accumulations of things like pet hair and lint, it is also more likely to be found on things that are not in regular use like the edges or underside of carpets.
They are also sometimes mistaken for bed bugs, as they can live on beds like bed bugs, and if you are contact with them long enough you may get a rash or bite like marks. If you are buying anything from an antique store or thrift store make sure to keep it separated for a few days before you bring it into contact with other things in your house. You want to make sure it shows no signs of infestation because those are the most common ways that they can be brought into your home.