Sometimes, a single lens solution works better- not missing the shot because you need to change lenses. Also, tends to make the wives happier- as she is not changing the lenses either. (she hates technical things, like messing with computers, cameras, pumping gas into her vehicle, etc...) You may end up with redundant lenses in the same ranges- but sometimes it is attractive to have one set of glass for higher IQ when it is called for, and another set for a general walk around glass. for example, I really find the 17/18-5x range too short for when outside- hate it- detest it. Everyone seems to recommend it - overall- but to me- it's way too short. Enter the longer zooms like the 18-135/18-200. Detested by lots on here- also liked by a number on here as well-- perfectly fine for what I am doing with mine.
EOS 5D III, EOS 7D,EOS Rebel T4i, Canon 70-200 f/2.8 IS II, Canon 24-105L, Canon 18-135 IS STM, 1.4x TC III, 2.0x TC III, Σ 50mm f/1.4, Σ 17-50 OS, Σ 70-200 OS, Σ 50-500 OS, Σ 1.4x TC, Σ 2.0x TC, 580EXII(3), Canon SX-40, Canon S100
Fond memories: Rebel T1i, Canon 18-55 IS, Canon 55-250 IS, 18-135 IS (Given to a good home)...