File > Save Scene

Saves the scene under its current name.

File > Save Scene >

Incremental save: When Incremental Save is turned on and you save the scene, a backup folder by the same name is created in the scenes\incrementalsave folder and a backup is made of the file that was previously saved to disk. Each time you save, another backup file is created. These backup files are incremental (filename.001.mb, filename.002.mb) so the previous backup is not overwritten. The number of incremental backups created is infinite by default.
Limit incremental saves: Applies a limit to the number of incremental backup files that Maya creates and stores. The default limit is 20 increments.
Number of increments: Type a value or drag the slider to specify a limit.

Note
When the Limit Increment Saves check box is turned on, Incremental Save stores only the limited number of incremental backup files. Once the limit is reached, Maya deletes the oldest incremental file and replaces it with the latest incremental backup file.