Even though it is middle of winter and spring is slowing coming, this is a great time to clean and check your equipment.
At this time of year, I pull my camera bag apart and reorganize it. I even go as far as pulling out the dividers and seeing if I can come up with a better way to keep my equipment. I also go through my equipment to find that certain piece of equipment that has not be used for maybe the last year, that piece then goes into a secondary bag that I bring when I think I may need that piece of equipment even if I don't use it too often. This sometimes frees up space for other equipment that I need on a regular basis. I then vacuum out the bag, trying to get all that dirt and dust that has accumulated over the past year. I then put the dividers back in, trying to optimizing the space.
After cleaning and putting the dividers back in, I start to clean the equipment itself. I start with the bodies and inspect them for damage and major dirt. I clean the sensor and the body itself. If the camera is not working correctly or maybe is 3 to 5 years old, I will send it in for a tune-up. They check the camera over, making sure it is working correctly and they will do a super cleaning of the sensor. I try to send the bodies one at a time or I try to send in one per year then the other the next year.
I then check my lens and clean the front and the rear element, plus I wipe down the body of the lens. If the lens is stiff or not as sharp as I think it should be, I will send it in for repair. I also check the front filter and if it is scratched or damaged I will replace it. After the major equipment is checked and cleaned, it is put back into the camera bag.
I will then check over all of the little miscellanies equipment, for damage and put that back into the bag.
Then the tripod is checked over and cleaned. If possible I disassemble the legs, clean and re-grease the fittings and reassemble them. The same for the ball head, it is checked and cleaned. (I do this a couple times of the year, especially if I am near the ocean and or beach). I also bring out my list of equipment and check it off and make sure I have all the serial numbers, I keep this list for the insurance company, in case something happens to my equipment. I keep a list for each bag of equipment that I have.
Finally, I check over any other equipment, clean it and put it back into its bag. I replace all replaceable batteries and check all my rechargeable to make sure they will make another year. I also replace all those snacks that did not get used with fresh ones. Now all my equipment has been cleaned and checked and good for another year of shooting.
So take a cold cloudy winter day to go through your equipment, clean and reorganize it for another year.