I have been using my bike for about 10 years for daily commuting and occasional traveling. It is a "trekking cycle" with a flat handle bars. I use it mostly for road riding, i.e. on streets and paved ways.
At the moment, it has original Shimano Deore LX shifters which are totally worn out. I am emotionally highly attached to frame/handlebar, etc. so I think upgrading is the way to go for me. This time it will be a major overhaul, i.e. I would like to exchange everything related to shifting / gears, and also rim/spokes, bottom bracket, hub.
I am now wondering which components to choose. I want to assemble things myself, so I am 100% familiar with the setup. I have been told that maybe an SRAM x7 group might be good, as it should be easier to work with with its 1:1 ratio.
Are there limits to the brakes/brake levers that I can choose? Must they "fit" the shift levers?
Are there problems I do not see? I.e. when switching from a shimano to a SRAM shift group?
PS: Hope this is all understandable, English bicycle tech vocab is not one of my strengths (yet).