Let us look at the pros and cons of the following sprocket:
11-28, 12-28, 12-29
These are the three sprocket for excellence dedicated to the climbs.
The first solution (11-28) is ideal for those who ride downhill too strong, or want a sprocket "universal" good for the plain like to climb.
The other two options allow you to have pinions not too far apart from each other. All three solutions are ideal for those who do not want to change sprocket depending on the type of route.
There are solutions lighter, have no pinions close to each other, but they are versatile and successful solutions on many occasions. A choice, no doubt, which focuses on the security of dealing with a certain tranquillity to any type of path; a choice when you are sure you really need to deal with challenging climbs.