It will only end when you want to.
When there is a new product that's getting some rave reviews I always take it with a bucket of salt. It does not mean the new one is always better, but when you hear something new to your ears, you might thought it's better. Di ba?
Know what you really want. In my case I always wanted to have a neutral setup from source to preamp, so I can hear the sound (or differences in sound) of my amps. If you want a colored preamp, then most likely yun ang hahanapin mo. Also, don't be influenced by reviews or friends. Kanya kanya tayo ng gusto.
If you don't know what you want to achieve in audio, not even god can help you
You probably stop when you don't have money.
ps.
Intimidated? Most of you don't know when we make a design we are (the Tono Men) the strongest critique. I remember when I got a comment from another who said, "ang sakit naman sa tenga ng tunog nyan" and we always take it as positive so that we can improve on the product. On the third iteration of the prototype biglang sabi "o anong ginawa mo maganda na ah."
Ganun talaga, kailangan pintasan. Kami ang numero uno pintasero ng product namin and we know the strenghts and weaknesses. Yung weaknesses, sometimes kailangan tanggapin because of design constraints, minsan pwede improve. Pero we also have products of the others kaya alam din namin how they perform
pps.
You also cannot discount the fact na may affiliation ang iba. May maka Mang Rod, may maka Rene, may maka AMX. Ganun talaga, influenced na agad.