Machine help

I’m going to look at a used machine soon. If the pressure and flow both match up to factory specs, is there anything else I should be looking at before buying it? I am definitely not a machine guy so thanks for any suggestions.

http://pressurewashingresource.com/vBulletin/residential/3278-buying-used-machines-dos-donts.html

Thanks Tim. Exactly what I was looking for.