Potential service problems 2007 SC430

[calvados6]

Looking for advice from longer term Lexus owners regarding incidental findings upon replacing a battery in my 2007 SC430 with 18000 miles, and in beautiful shape and has no other service issues.

The radiator was found to have a small leak with coolant along the lower seam, and there was the additional timing belt and water pump replacement recommendation, even though the car is low mileage, since the car is 11 years old.  Would you tackle all 3 items at once just because the mechanic is in there, or just fix the current but not acute problem, which is the radiator?