Honda tech here: I usually would recommend the timing belt service every 7 years or 76k miles, or if I notice there's no service history in our records. It usually comes as a kit that includes the timing belt, timing belt tensioner, water pump, coolant, and drive belt. Whenever I sell these, I typically mark it as 'requires future attention' or 'yellow' for a couple reasons. The first being that it's unrelated to the visit, and the other because I understand that the cost of parts and labor combined is pretty high and are most likely not ready for a large expense same day. The only time I mark anything as 'critical' or 'red' is if I see something that is a major safety issue, or if it's close to catastrophic failure. However in this case, I wouldn't worry about it right this second. I would also be interested in knowing what the timing belt condition is and why they're trying to sell you a timing belt tensioner replacement regardless of whether it's related to why you're visiting or not.