How many channels do you need in a 'scope?
My answer would be zero, ...
Sub-question: What do you use it for?
... because as an entry level hobbyist i do not really need an oscilloscope. It is more like an expensive toy for me.
By now I have only an analogue one which actually has 4 channels (two of them only 0.1 and 1 V/cm) but i did not use them. As tautech wrote in the Siglent thread:
"
Horses for courses"
From a hobby point of view, the oscilloscope is not primarily a work horse. The question is not "do I really
need this or that feature", but more like "how much fun is it to display things this or that way". And displaying many signals simultaneously is getting you prettier pictures. This is what makes a four channel coloured TV more enjoyable than some other banner specs.
Edit: Oops, I forgot an important word ![Smiley :)](https://www.eevblog.com/forum/Smileys/default/smiley.gif)
Lissajous figures are also something you will
not really need much of an oscilloscope today, but creating them on an analogue one is like a piece of art. I can very much enjoy to watch them.
[...]
I did say "A one channel scope without an external trigger offers little more than a 2.5 digit DVM for practical purposes", [...]
Well, not that I would want to recommend buying such a scope, but I would rather disagree on that statement. My DMM is the BM257 (the same as used by Dave in many of his videos) and although one of it's features is a Crest (Peak Hold) mode, it is not able measure ripple voltages of SMPSs:
"CREST Mode Accuracy: Specified accuracy plus 150 digits for changes > 5ms in duration."
and the AC Voltage is defined as "50Hz - 400Hz"