Heh. I remember the day when a TTL of a week was pretty standard. Anyway, the since the NS records for a domain come from the next level up, i.e. in this case

Heh. I remember the day when a TTL of a week was pretty standard. Anyway, the since the NS records for a domain come from the next level up, i.e. in this case the .com nameserver which are also the root nameservers, if they had a short TTL then those root nameservers would get hit pretty hard. Also, it isn't your choice what the TTL on your NS records is, it's admins of your top-level domains.