Do you like mountaineering?
I wouldn't say I am an avid mountaineer. However, hiking in the mountains  and scrambling up short rock walls can be thought of as a simple form of mountaineering, so I enjoy that.
When is the last time you went mountaineering?
stamina and level of commitment required, and the difficulty of protecting the climber. Different grading systems consider these factors in different ways, so no two grading systems have an exact one-to-one correspondence. 
Climbing grades are inherently subjective. They may be the opinion of one or a few climbers, often the first ascensionist or the author(s) of a guidebook. A grade for an individual route also may be a consensus reached by many climbers who have climbed the route. While grades are usually applied fairly consistently across
preface, Phelps advised readers of the prerequisite "background in functional analysis": "the main rule is the separation theorem (a.k.a. [also known as] the Hahn–Banach theorem): Like the standard advice given in mountaineering classes (concerning the all-important bowline for tying oneself into the end of the climbing rope), you should be able to employ it using only one hand while standing blindfolded in a cold shower." Phelps has been an avid rock-climber and mountaineer. Following the trailblazing research