I took a random glance at my router's logs and noticed a whole lot of lease renewals from my Tivo. How many? How about 7829 DHCP renewals over the past 11 hours.

I found one thread on the TivoCommunity forum, but it's not terribly helpful in diagnosing the problem. They suggest that it might be a problem with sproradic network connectivity. I've got my Tivo hooked in via traditional, wired Ethernet. The Tivo is plugged into a four-port switch that it shares with my AppleTV, and I'm not seeing crazy renewal rates from the AppleTV (only six DHCP renewals over the same time period, which is still higher than it probably should be, but is still reasonable). I even have a static DHCP reservation, so the Tivo always gets the exact same IP address.

Any thoughts on possible causes or likely solutions? Or, should I just file this under the "yeah, whatever" category and go on with life?

I think the first thing I would do is check speed/duplex on all the ports from the tivo to the router, inclusive. If you're unable to check them, try (temporarily) swapping connections to different switches.

You might also check for errors on those ports, if possible.

That's a renewal every 5 seconds. A lot.

How long is your lease? 6 over 11 hours for the Apple TV is not unreasonable for a 6 hour lease. For some reason I've never bothered to work out, I see renewals always less than the lease time.

What do the actual logs say? Is it something like the Tivo is requesting an address and the router is trying to deny it possibly?

This is expected. DHCP clients generally renew the lease before the expiry time is due. A bit of quick googling suggests that the renewal time is often 50% of the lease time.

Yeah thinking about it, it could be intentionally randomised to spread the load on the server. I have no issue with it - just something I noticed.

I don't see any easy way of knowing what the expiration time is, but I'll note that my wife's laptop (running Windows XP Home) is renewing its lease approximately 200 times per day. That does make it sound like the leases are too short, yet I have the GUI set to a 240 minute timeout. I'm not sure what else I can tweak beyond that...

Meanwhile, I "solved" the Tivo problem by giving it a static IP address. It sure would be nice to know what's actually going on.