If you are in either of these two situations, it may be best to use a window cleaning service instead of trying to clean your home's windows by yourself.
You have mobility problems
Lots of health issues can impair a person's mobility. If, for example, you have arthritis or you have a herniated disc in your back, you may not be able to move about as freely as you once did, due to the pain and stiffness that your condition causes.
In this situation, it may be best to arrange for a company that offers window cleaning services to come to your home and wash the windows for you instead of trying to clean them yourself.
There are two reasons why you should not attempt to tackle this job if your mobility is impaired. Firstly, window cleaning is a very physically intense form of work that can be challenging even for those who are very flexible and strong. If you try to undertake this task in your current physical condition, you may exacerbate your symptoms and impair your mobility even further.
For example, if you have a partially-herniated disc in your back and you try to stretch upwards to reach and wash the top of a particularly tall window, you may end up causing this disc to rupture. This could leave you in extreme pain and unable to move at all for weeks on end.
Secondly, your impaired mobility may make it difficult for you to do a thorough job.
If for example, you have arthritic shoulder joints, it might be hard for you to use the squeegee to wipe the suds off each of the windows, as the stiffness in your joints may make it impossible for you to perform the required movement. This could leave your windows streaked with dried-on suds.
Your home has three or more storeys
If your home has three or more storeys and the windows on the upper floors need to be washed, then it is definitely best to have a professional clean them.
The reason for this is that a ladder is not generally considered to be a safe or suitable form of access equipment for instances in which you need to clean windows that are positioned many metres above the ground.
As such, if you were to tackle this job on your own, you would need to rent a domestic scaffold, assemble it by yourself, secure it to the wall (to prevent it from toppling over when you stand on it) and then dismantle it again when you have finished cleaning the windows.
This could be a very complicated and lengthy process, especially if you have never used scaffolding before. Renting this equipment is also likely to cost just as much (if not more) than paying a window cleaner to do the work for you.
In this situation, it would probably be easier and less expensive to use a window cleaning service.