In what ways do the professional repairpersons stand better than ourselves?

If the Sliding glass door repairs The Mornington Peninsula , a professional could fix it wisely than ourselves due to the following factors.
Understanding of the issue
Your doors could go wrong in a finite number of ways. Each of these issues will require a different approach to end up with a solution. If you sit and analyze the defective door mechanism, you may be able to find one or two issues. However, mostly, you could not find the root cause itself. Hence, you should spend a lot of time finding the problem itself. But as the professionals are dealing with these doors for their entire life, they can see the issue with their naked eye that you could not do. So, they will apply the necessary solution to the issue and will get it resolved within a few minutes. This understanding of the problem with your doors will be missing when you repair your door yourself. So, it is better to go to a professional.

Time delays
If a task requires a minimum of few hours from your life, it is better to check whether there is no other option to complete that task thus saving your time. Repairing your defective sliding glass door is the perfect example. You have nothing to do with these repairs and it will take you hardly several hours to complete that too in the rare case. On the other hand, if you call a professional repair company, they would complete the same process within a few minutes due to their expertise in the activity. So, it is intellectual to handover the repair activity to the professionals themselves.
It is not fair to get the same issue again after a few days of repairing your doors yourself. So, you should go to a professional for the quality of his work.