I use RTM to keep track many of my life maintenance items, whether it's getting a haircut, changing the oil in the cars, replacing the HVAC air filter, or getting my allotted free credit report.

In my Maintenance list, I have the following tasks:
* Get Free Credit Report
* 4Runner Oil Change @ 302,000 miles
* RX300 Oil Change @ 192,100 miles
* Haircut every 2 months
* Replace furnace filter every 3 months

For each item I have a detailed note with the details on when I last performed that item and in some cases other pertinent info. For the furnace filter, the note reminds me of what size to purchase (12x20x1). Just this morning I replaced the filter and then set the due date to "+3 months" which converted to "Fri 8 Jan 2016".

For the oil change, the note says something like:

Interval is approx 6,000 miles or about 12 months.
Change history:
186,100 on 4/23/2015

I can then decide when to change the oil based on the time or miles since the last time (and when I have a spare moment).

For the free credit reports, as you may know you can get one free credit report a year from each of the three main reporting agencies. I spread them out during the year requesting one every four months. The task has the date of the next report to request and the note has the details. Here's an example of the note (that URL is provided by FTC.gov):

Free Credit Reports
https://www.annualcreditreport.com/

Each agency one free report per year. Next up:
10/14/2015 - TransUnion

Last report requested:
06/14/2015- Experian
02/14/2015 - Equifax
10/14/2014 - TransUnion

As far as the haircut goes, it's always pretty obvious looking in the mirror when I need to get the hairs chopped, but I do find it helpful to know when my last haircut was and I keep that in the task's note.