First of all..removing treatments or inventory from the Tx or Rx lists will not effect whether they appear in a patient's medical history, and does not break the "who got" as long as you can find a patient that has the treatment or item in history later after you have deleted it. You should always remove treatments and items before deleting the category in full that they are stored in, otherwise you will likely get index rebuild errors about treatments or items that do not have a category. Also I never recommend putting obsoleted treatments or items in an obsolete category because of what it will do to your income reporting. I recommend putting a - Action Code of course to obsolete it. Then I add two (2) small zz to front of the description of the treatment or item. Ie: zzAntibiotic 25mg to make it harder to see as it pushes the treatment or item to bottom of the category it is located, but keeps the income for these in the same category, where it always was, for historical purposes. If tracking of anything is unneeded historically, then go ahead and obsolete and delete as mentioned above. Also be very careful with touching any Treatment or Item that has an associated Reminder or Remind As connection. This is of course another topic altogether.
Again, if you want your income reports to stay ok for years going backwards, you should not move things into a giant Obsolete category, but leave them in the category where they always existed and zz the description and obsolete the treatments or items as in an example I have above. If your owner doctor(s) says retrospective reporting of income is not that important, then do as you wish.