Eventually they really need upgraded. Mostly because you will hit the usage limit a ton, They do make more money, but like so little more that it is hard to even tell. You can also upgrade your medications. but that is pretty much useless. They say you will need to use less medication, but it hardly even effects it and costs a ton to upgrade. For an example... Level one is 10% cure level 2 is 13% that means that if in level one you had to give 10meds, in level 2 you will need to give 8, but it costs like 400 to do. You could just buy tons more of the med for that
Doing "Bloodwork" is the best way to earn more money. Send your "MRI" patients to the pharmacy so you can keep getting ward patients into the Lab. This will be the best way to get more money without using your "real" money. Having more colleagues and "helping" them, buy clicking on them and doing search missions, will help you get the energy to do this. Hope this helps and have a good day.