Notice to my future self: The default interval between two runs of puppet is 30min or 1800s. In case this is too short you can add something like:
runinterval = 28800
to the [main] section of the puppet client configuration.
If you want to do this automagically, just run the command
puppet config set runinterval 28800
on each client.
Another command you might want to remember:
puppet agent --configprint runinterval