Rubber roof questions

I just purchased my first travel trailer. I'm not a beginner but I've always had motorhomes. All my previous rv's have had fiberglass or other type roofs. This is the first rubber roof. The trailer is an 04 Fleetwood wilderness 32'. Its in incredible shape but has sat the last 6 years. I want to clean the roof and make sure I keep it in shape since its had no care the past few years. I went to a local rv shop to get some recommended supplies. The gentlemen pointed me to a couple products then told me that if after I wash it to wait a day. After that to take my finger and if the roof gives off any white chalk to my finger the roof needs replaced. Now that just seemed a bit much to me. So I come here to ask the experts. Is this the case? Is a white chalk the death nail to my roof? It has zero leaks and I just can't imagine it would need replacing so soon. Is there a coating I can apply to the roof to make it last, and finally what should I really do maintenance wise to keep it healthy? Thanks in advance