I once got a 60ml vial of adex that lasted me a couple years, was still potent at the end.
About the only compound you sometimes see as a liquid I'd only use as a solid cap is cabergoline. Its just not stable or effective as a liquid.
Otherwise I've tried tamox, exemastane, sildenafil and tadafil as both liquid and capsule and didn't notice much difference
most liquid solutions have a long shelf life as they have an alcohol component that acts as a preservative, unless it is a compound that simply does not work as a liquid solution (liquid cabergoline for example).
ive used liquids with mixed results, ill stick to tabs for now, also depends on supplier mostly i guess
it depends on the source. But for me, I try to go with hg on my pct stuff, otherwise with reputable ug. research liquids is my last resort.