Relevance, in the Oxford dictionary, is defined as "the quality or state of being closely connected or appropriate".
When it comes to hotel service, it means whether what you are talking about, offering, suggesting or recommending matches with the guests' needs or wants.
For example, do not simply state that there is complimentary tea time during the weekends when the guest is only staying the weekdays. That is, unless you are saying it in a way to entice them to return in the near future, and not simply because you are regurgitating the same scripted speech to every other guest that you handle.
If the guest has already said that she does not take cheese, why are you still recommending the burrata salad, unless you are saying that the magic is in the dressing and you offer to swap out the burrata for something else of equivalent value and of complementary texture as well as flavour.
Upgrading the single guest or couple to the two-bedroom unit is incompatible, unless you are willing to set up a massage bed in the second room and include a treatment? And even if you are willing to do that, does/do the guest/s like massage in the first place?
Usually in the restaurants, the service staff will highlight the recommended dishes. But come to think of it, using the word "recommend" means you are proposing something for the guests. How can you do that without knowing what they like or don't like? (Hence, it is smarter to first ask about their preference or craving for the evening before recommending something that is suitable.)
Reflective thoughts: Think about all the possible irrelevant service that could take place in your department or section. Observe and listen more to the things that are being offered, suggested or recommended to the guests. Work with the team to eliminate irrelevant service from happening!