A lot of the time when you hire someone for AC repair they are most likely going to do a pretty good job of it. However, there are going to be other occasions where they would do a much worse job than might have been the case otherwise, and there are a number of things that you should keep in mind here. One thing to always remember is that the servicemen that work in this field usually charge per task. For example, if you need to get your refrigerant replaced then they would have a set charge for that, and if you need your unit serviced there would be separate charges for that as well.
This means that if your service provider tells you that there is a lot more work to be done then there is a pretty good chance that they are only saying this so that they can get more money out of you. If you hire someone to do a specific task but then they start suggesting other tasks that they could do, they are pretty much only trying to rip you off.
Before getting more work done, just check your AC and see if it is working after the basic task that you asked to be performed. If it’s not working quite as well as you would like this means that the extra tasks are worth it. If it is working fine, however, without any ice forming in the evaporator coils and without any water dripping, this means that you can rest assured that the work done was satisfactory and you don’t need to pay for anything extra since it won’t really do any good.