4 Answers. From multiple sources, it looks like the merchants' restock rate for gold is 5 days.

Do merchants restock Gwent cards?

1 Answer. Only a finite amount of Gwent cards exist in the game. They can be obtained by buying them from innkeepers or winning against opponents in a game of Gwent. However, vendors never restock on cards and opponents never award more than 1 card.

Who is the best merchant Witcher 3?

You can find a librarian named Marcus T.K Hodgson in Novigrad. He will buy all your books at a higher price than the rest. This is the best place to sell your books if you need extra space for your weight.