How can I stop 2-in-a-row backups each hour?

Question

Each hour for several months now, my Macbook Pro performs the normal backup, going from Preparing Backup to backing it up, to Finishing Backup. But then an odd thing happens; the cycle promptly repeats, regardless of whether or not I changed anything on the hard drive (nor should that matter). The second round usually involves the same or barely less storage space to backup.
Since Apple doesn't provide a method of setting the interval of backups, I'm at the mercy of the software either being On or Off. When I'm about to leave the house and I see "Finishing Backup", I figure I'll let it finish the backup before leaving. But then I see it try to start again.
I learned that I'll end up late to events if I trust it, so in recent weeks, I started to stop the backup. It reports that it's stopping the backup. Then, if it was the first attempt at backing up, it starts preparing a backup immediately upon having reached the end of the stopping backup process. I have to tell it to stop twice in order to make it actually stop. This is getting annoying enough to post my first topic ever on here.
I don't recall any significant change to my system from the time when it used to just perform a single backup to when it does two each hour.

Answer 1

JimInIowa wrote:
Thanks for pointing me to TimeTracker; I always wished the contents of the backups were more transparent.
Yeah. Why something like that isn't built-in is a real mystery.
My backups weren't taking terribly long, but a wireless backup of even 50 MB can eat up somewhere on the order of 5 minutes from Preparation through Finishing.
I don't have a TC, but that seems much too long, even for wireless, unless there's some sort of conflict (such as downloading big files on the same connection).
You might want to take a look at the things in item #D2 of the Time Machine - Troubleshooting *User Tip* at the top of this forum. One (or more) of those have made large differences in many cases.
It's also worth a look at TM's logs (as mentioned in #D2, and another facility that ought to be built-in). If you see something suspicious, copy and post them here.
If I actually modified real real files, it obviously takes longer as it has more to store. But the reason it bothered me was the times where I did nothing but browse the web and had to wait for roughly 10 minutes of backups to take place each hour. When you just want to pack up and leave with the laptop, you hate to stop it, much less have to do it twice; but waiting 10 minutes for nearly no benefit also seemed stupid.
Other than doing an abnormal shut-down, cancelling or interrupting a backup won't hurt anything.