The concept if trying to maintain a 150 polish maximum is strangely exciting... Though I wonder if it's doable. Self control has never been one of my strong points and my collection is currently nearer 600. But realistically, do I need 600 polishes?
One polish that would be a strong contender for my top 150 is Essence Colour and Go Irreplaceable.
Could you cull your nail polish stash to 150 polishes?