Do you also keep track of the life cycle of different brands ...
Do you mean the equipment lifetime (in years)? Surely such a figure is intially planned (estimated, anticipated) ... and is only known for sure "after the event" (once the equipment has finally given up, and has been junked)? And even then may well be a "one off", and not not truly representative across the "brand" - which, in any case, may have "moved on" (or even "up") after the passage of a number of years.
Apart from anecdotal (or personal) bias
... perhaps based on previous experience, or the reported experience of others - as well as perceptions based upon such factors as low (relative) price and what looks and feels like "poor quality" - how can we say initially that one brand is likely to have a shorter in-service life when compared with any other?
Other factors (such as maintenance - or lack of it, availability of parts, service support, user care and attention [or abuse], lack of use [sitting in the stores for most of its life], heavy usage ... and no doubt many more "unknowns") usually apply.