Persistent cookies have been criticized by privacy experts for not being set to expire soon enough, and thereby allowing websites to track users and build up a profile of them over time. This aspect of cookies also compounds the issue of session hijacking, because a stolen persistent cookie can potentially be used to impersonate a user for a considerable period of time.

Alternatives to cookies
Setting a cookie
तिऱ्हाइत स्मृतिशेष
Cookie expiry