Do I need a separate protectant, or is an all-in-one cleaner enough?

For weekly maintenance, an all-in-one like Chemical Guys Total Interior or Adam's Total Interior is fine and saves time. For deep cleans on heavily soiled interiors, reviewers across detailing forums consistently recommend a dedicated cleaner first (like P&S Xpress) and then a separate protectant with UV inhibitors, since combo products tend to compromise on cleaning strength.