You may be noticing numerous, small (~2-3 mm), round critters crawling along window sills lately -- I know I have been! If so, they are likely carpet beetles (Dermestidae: Anthrenus sp.).
The ones seen at windows are the adults that developed from larvae commonly found in homes. In the spring, when flowers begin to bloom, the beetles attempt to leave houses by finding sunlight, thus their attraction to windows. Once at the flowers they feed on nectar and look for mates.
Though adults aren't damaging (regardless of the nuisance they might pose), large numbers may signal a large population of their larvae in the home.
These beetles live a long time as larvae, crawling around floors and in containers without a good seal. They feed on wool and other furs, feathers, dead insects, and other protein-rich organic materials. In a study we did several years ago, we found 100% of the surveyed homes had these larvae, but some have more than others.
Larval carpet beetles can damage certain animal-based textiles, so large numbers may destroy items of value. For more information on fabric pests, please see this NC State fact sheet.
By the way, I posted the following tweet last year at almost the same exact time that I noticed them this year. Thus, early February appears to be the beginning of adult carpet beetle season!