Like most things it is important to care for your cast iron, without care the cast iron will eventually rust and look untidy.
Periodically wash your cast iron with soapy water and occasionally wipe over with an oily cloth I use 3 in 1 oil. This will keep your products in good condition. Any moving parts should be periodically oiled.
When your purchase does show signs of rusting or looking untidy simply give it a few coats of suitable paint, with the proper care and attention you purchase should last years.