ssh and dhcp interactions?

I'm wondering if I'll have ssh complaining about hostkeys if
I boot up servers with IP addresses assigned from a pool
by DHCP?

The reason I wonder is that examination of a typical ~/.ssh/known_hosts
file shows each line has a name and an IP addr.

If the IP addr is different the next time I talk to the machine
with that name is it gonna complain? Or want me to add a new
known_hosts entry with the new name,ip pair? Or complain that
some other machine had that IP the last time it recorded an entry?

I'm just trying to figure out how much trouble getting away from
static IPs might get me into before I find myself sinking in the
swamp :-).

Thanks for any info you can provide.