There are two elements of a comfortable saddle:
one that fits your butt and has the right amount of padding for your use
and
one that gets enough use that your butt gets conditioned to it.
My saddle disappears, but I have about a bushel of saddles that didn't, not including probably 25 that I sent back after trying them. I'll mount a trial saddle and give it 1/2 hour on my rollers. If it passes that test, I'll try to ride a century or close to it on it. If it passes that test, I'll give it a try and see how my butt feels about it over time. For sure it's impossible to tell if a saddle might be suitable until after the 3rd hour. If it's not comfortable then, try another one. That's assuming that you already ride enough to have a cyclist's butt.