For many motorists the air conditioning system in their vehicles is never switched off - summer or winter.
While some will say letting it run consistently will have a negative influence on fuel consumption, the argument against that is it provides occupants with all-year-round safety and comfort benefits.
For me, I'm in the leave-it-on camp.
A comfortable and relaxed driver means a more economical driver in my book. Besides, there are plenty of other ways to improve on fuel consumption.
Try throttle control and having the tyres inflated correctly.
But having air conditioning (A/C) installed and left on, or even used sparingly, does carry some potential health risks.
While we may sit in our motor vehicles in congested traffic and wonder how all the surrounding harmful environmental fallout is affecting pedestrians and cyclists, the reality is, trapped in your own little bubble can be even more damaging to your health.
Stuck in your vehicle, your respiratory system is exposed to either the outside nasties (including diesel particulates) or if the A/C is on recirculate, a continuous supply of already contaminated air.
Pollen or in-cabin filters have become pretty much a standard feature of A/C systems these days and should be replaced at regular intervals. Like the air filter on an engine's induction system, they are designed to trap airborne contaminants.
In the case of an engine, it's clean air into the combustion chamber but in the case of an effective in-cabin or pollen filter, it's the respiratory system that is going to be the recipient of a less contaminated air supply.
In the big cities especially, drivers and passengers are spending a lot more time in stop-start traffic, especially in peak hours, so if you suffer from allergic reactions, frequent headaches, hypersensitivities, sinus congestion or have any respiratory issues it would pay to get your A/C system checked regardless of how long you keep it switched on.
If you suffer from airborne allergies you are also at higher risk of travelling in vehicles with contaminated filters or those with a high build-up of mould, mildew and bacteria in their ventilation systems.
Keeping the interior of the car clean and a smoke-free zone is also highly recommended. And if you are purchasing a used vehicle, get the filter checked. It may give you a heads-up on the general condition of the A/C system and any possible future servicing costs.
If your vehicle is still fairly new and being serviced by the franchise dealer, then most of the service staff will recommend a new pollen filter be fitted at every service.
I'm not convinced it's a must-do on every service, however.
Like a lot of other service items an awful lot depends on age, distance travelled and the environment a vehicle is being exposed to.
Hopefully you have a service provider who makes these recommendations for all the right reasons.
Many of the non-franchise garages would not even think about the pollen filter during normal servicing, especially on the older fleet, as it is not usually part of their normal routine.
This means there is a high chance you have a highly contaminated and dirty A/C filter if your service provider hasn't mentioned it already.
Once you have been shown a badly contaminated pollen filter you won't need any more convincing about getting it replaced ASAP.
What about the A/C system itself then, how often should that be checked? The A/C specialists I have spoken to say the more modern systems of the past 10 years or so are a lot more reliable and require less servicing than the early units.
A system check and gas top-up once every two or three years will ensure the system remains in good working order, while an additional service to treat for bad odours, plus mould, mildew and bacteria in the ventilation system is recommended.
It's not overly expensive either, around the $160 mark according to my sources.