safety net when working on a dedicated server

Hi all,

I want to start modifying iptables rules on a dedicated
Linux server.

What would be an easy and more or less bullet-proof
way to be sure that if I mess things badly I will always
be able to reconnect to the server?

I was thinking of an automated task executing the following
line automatically on the dedicated server every hour or so :

iptables -I INPUT -p tcp --dport 22 -s STATIC_IP -j ACCEPT

so even if I mess things badly, after maximum one hour I know
that this line will be executed and that I'll be able to connect
to the dedicated server once again (problem is every hour a
new iptables rule gets added... which will add after years of
uptime ;)

Any tips / hints?

Thanks in advance for any help,