Most cabinets have a thin lacquer-type finish that rubs off edges of heavily used drawers and cabinets within a few years.
Homeowners can protect their cabinets by varnishing the cabinets with a good-quality oil-based varnish such as McCloskey's Man O'War varnish. Any similar brand that is used to protect boats in sea water can be substituted.
Oil-based varnishes, however, tend to turn amber/yellow as they age so I will rub the old cabinets with a red-based stain (red oak) before varnishing with an oil-based (yellowish) varnish.
If some areas of the old cabinet finish have been rubbed off to raw wood, you will have to restain those areas to match the existing cabinet color before proceeding to the re-varnishing tips.
The main thing is to put on a coat of heavy-duty oil-based varnish that will hold up to food chemicals, steam and cleaning chemicals.
Answer for Kitchen Cabinets
The possibility of restaining depends on what the cabinets are made of. You mentioned "not real wood", this is a concern. There are some cabinets that have a vinyl wood looking covering. I don't think it is possible to drastically change the stain color with this type of cabinet construction. (I could be wrong.)
If the cabinet has a thin wood covering, wood veneer, then it is possible to change there color, at least a bit. Check out these pages for more information;