You can manually configure how frequently you would like your model files autosaved by accessing the Autosave and Recovery dialog from the main Options menu in the Editor.
The Autosave and Recovery dialog
The option to Save Backup Copy of Model Files Every n Minutes is checked by default. You can unselect this if you prefer not to make use of the autosave functionality, and you can also determine how frequently you would like to update the autosave files (every 5 minutes by default). Another way of looking at this is to consider the maximum number of minutes of work you could lose since the last autosave!
Another option is to Autosave the Final State if I Close Without Saving. Again, this is checked by default and is particularly useful if you choose not to save before closing a model, and then realise too late that you have made a mistake. If this option is checked, it will ensure that the final state at closing is autosaved in case you have second thoughts after closing a model.
You can also choose to Show Autosaved Files from this dialog.