Again, I apologize for coming late to the thread.
"Disposition" is NOT disposal, but disposal may be one of the options for disposition.
Let me explain:
In the sense used in this thread, this definition from the US government may help
Disposition. The actions taken regarding records no longer needed for current Government business. These actions include transfer of records to a Federal Records Center; transfer of records from one Federal agency to another; transfer of permanent records to the NARA; disposal of temporary records; or occasionally, donation of Government records.
Disposition authority. Legal approval empowering an agency to transfer permanent records to the NARA or carry out the disposal of temporary records. Approval must be obtained from the NARA.
So, "disposition" essentially means "changing the position" of the records.
Some documents and records are kept forever (corporate charter), some for a definite time (tax records, quality inspection sheets), some for an indefinite time (sales proposals, old telephone bills.)
The task of record keeping is to determine as much as possible
(when the record is first stored) how long the organization will hold that record before pulling it out for "disposition" review. At that review
(which could be days, weeks, months, years, in the future), the
organization makes a decision to keep the record as is, convert it to another form (scan or microfilm) and retain it, or to transfer it to someone else, or to destroy it.
The tricky part is merely keeping track of each record's review date. Since different types of records have different holding periods, the review periods also vary. In the days of hard paper copies, hordes of clerks used to keep elaborate cross-index files and tickler files to identify and retrieve records for review at the appropriate time. Modern computer systems can do all that with far fewer errors and much less cost.
Ultimately, someone with appropriate authority (equal to the importance of the document) has to be part of the review process.
I hope this helps you determine what to do when someone tasks you with "disposition" even when that person has no clue of the real meaning of the term when used in regard to records.