I really enjoy the natural rhythms of the seasons. There are many things that should be changed every three months or so, and aligning those things with seasonal changes helps me to remember them without having to write them down. They range from some fairly gendered concerns to common sense things for all. Here is my list, in no specific order, and by no means is it exhaustive.
1. Change your toothbrush.
This one is for everyone. It is recommended that you change your toothbrush every three to four months. If you keep it at three, you'll align with the seasons, and bam, new weather patterns? New toothbrush (or toothbrush head, if you have an electric model).
2. Change your mascara.
The recommended shelf-life of mascara is not to exceed four months. I remember reading a tip, and I'd like to attribute it to Beauty @ About.com, but I can't find the exact article--anywho, the tip was to sign up with Amazon.com's Subscribe and Save program, if you are bad at remembering when to go for a new mascara. The plan is to subscribe to a new mascara every three to four months, and then, like magic, when you are supposed to throw your old mascara away, a new one shows up! If you don't want to align with the three-month seasons, this is an excellent tip. My current favorite type of mascara isn't available through that Amazon program now, though, so I bought it at the local drug store instead, and I'm ready to crack it open June 1.
3. If you wear contacts, change your contact case.
I found this article about eye strain and work computer usage a little over a year ago, and it kind of changed my world. In the article, along with lots of good every-day tips, it says, "Clean your storage case regularly (with fresh solution, not water) and replace it every 2 to 3 months." Um, what? I have never, ever been told this by any eye care professional. I googled and found that to be the true and common advice, and much to my horror, upon reading this article, I don't think I'd ever changed a contact case unless forced to because I lost the first one. It makes sense, though, and that's why every bottle of solution you buy usually also comes with a shiny new contact case. I have a giant box of them, now, and when the season changes, I'm going to change the case. I may also change the contacts as well!
Here is the article:
4. Change your scents.
This is in regards two of my favorite collectables that are based around the olfactory sense--candles and hand soap. Those are the two big things that are scented seasonally around my home. Smaller instances are things as varied as shampoo and conditioner, body wash, hand sanitizers, dish soap, counter-top sprays, fabric refreshers, and air fresheners (which I prefer in my home's restrooms to candles). If one is going to take the time to invest in all of these products, one should make sure to use them as well! Switch everything around every three months, and you'll be ready when the weather really starts to match the season.
5. Change (or restock) your baking supplies.
I'm not citing anyone but myself on this one. Every three months, I like to take inventory of my flour, sugar, brown sugar, powdered sugar, tapioca, salt, baking soda, baking powder, and vanilla extract. Especially coming up on fall and winter, I like to make sure I have at least a backup of all of these products, so I don't run out when I need something.
These are just a few things on my list. Is there anything that you like to check quarterly that can fit into a seasonal time frame?
I think I notice my mascara actually gets goopy and harder to change around the three month mark--I probably change it for that reason more than for the health reasons, lol.