The secondaries will handle it, right ?
With a previous hat on, I'd got DNS all sorted out - still manually editing files, but had a master list and a script that would build a new master config for our master BIND server, and update the config for remote secondary services we had with a hosting provider. Apart from the occasional issue of someone ignoring instructions (especially on how to update the zone serial number), it worked well - much better than the manual process that was in place when I started there. When I started there were over 1200 zones - by the time I'd cleaned things up we were down to about 650, I'd also written scripts to spot "dead" zones.
So all running swimmingly for many years, and then I was made "redundant" - quotes because while it was technically redundancy, it was really a situation engineered by one person to get rid of what was left of the engineering department.
Anyway, as soon as I left, the idiot manager responsible for getting rid of everyone with any technical skills and who thought he was ${deity}'s gift to computing set to deconstructing everything I'd built because, he didn't understand "Linux and all that s**t" and hated that I had built reliable stuff that didn't run on Windoze. So he just pulled the plug on the DNS server - working on the basis that the secondaries would keep serving everything. Now anyone who knows anything at all about running DNS already knows what happened next ! Yup, a week later, the secondaries expired the zones and they all stopped working. Oh how I chuckled to myself when one of my old colleagues told me what had happened. Best of all, one of the zones affected was their own - and when that went, so did a few customer services (some customers lost VoIP phones).
I do wonder what lies the idiot manager told affected customers - I know for a fact that he won't have admitted any fault on his part, probably blamed it on the hosting company. Best thing is, for a few clicks, he could have made the secondaries into masters with a few clicks of their web UI had he done it before killing the master. He couldn't even power the server back on, he'd already ripped out all the networking as well.
That was how he approached changes - do stuff and fix problems when the customers phone in and complain !
But not my problem any more :-)