Network logs kept for a specified period of time.  Retention times are listed below:

Firewall network address translation (NAT) snapshots are taken approximately once a week.  They are kept for 30 days.

Cisco Clean Access login data is kept in files that are separated each week.  They are kept for 30 days.

DHCP lease records are kept in files that are separated each week.  They are kept for an indeterminate length of time.

Network device error logs are kept in files that are separated each week.  They are kept for 6 months.