W2k3 DHCP Lease Durations & DNS Refresh Intervals

Is there (or should there be) a relationship between the DHCP’s Lease duration and DNS’s No Refresh and Refresh Intervals? Should they all be the same? For Example, if my DHCP Lease
Duration is 7 days, should my DNS No Refresh & Refresh intervals be both set to 7 days also?

Anyone care to share what they’re doing in their environments?

Thanks.