Texas Instruments TI-83 Plus Manual page 123

Chapter 2: TI-83 Plus Specific Information
What should applications do?
Most applications should be able to use the CleanAll routine to manage temporary
variables. Applications should make a call to the CleanAll routine as soon as all
temporary variables in use are no longer needed. This is especially important if
temporary variables are going to be created in a looping environment. If the temporary
variables are not cleaned before the loop is restarted, RAM will become full.
If some temporary variables are needed to be kept alive for extended periods of time,
make sure that any other temporary variables that may be created by the application, or
returned from the parser, are at least marked dirty when they are no longer needed.
That way, the RAM they take up can be reused if needed.
It is also good a good practice to try and use the Ans variable instead of temporary
variable. The StoAns routine can be used to store to the Ans variable.
TI-83 Plus Developer Guide
113
Third Release May 28, 2002