any shop owners/retail seeing more demand in refillable pod?

Had a few customers mentioned 8-10ml capacity, they thought that was ideal size. They didnt ask much about the flavor but mostly care about the quality, battery life, convenience, longer use for refills, etc. I tested a device called ELFX Mega, which turned out great, 10ml refillable in, large battery. with all the noise about these products in the UK, I think now the customers attitude slowly change to long-term usage now. Is it becoming common across diff parts in the UK?