If you do not like the aggressive way Time Machine does it’s backups (on an hourly base) you can change this. It is possible to to this by using the command line (terminal). So start the terminal application. On the prompt you can issue a command like this:
sudo defaults write /System/Library/LaunchDaemons/com.apple.backupd-auto StartInterval -int 14400
where 14400 is the interval time in seconds, here 4 hours. If you want to let the backup happen hourly use 3600 and so forth. If you don’t like the command line, you can use the free tool TimeMachineScheduler.