fudjj and I tend to differ on this topic. I say, sell whatever will make a buck.
I broke my back for a year or two trying to break into computers and electronics. Fell back asswards into selling from Newegg when they were much cheaper than eBay on some niche computer products... 939 socket.
and video cards.
Buyers/Sellers in France and GB loved me.
That lasted about 6 months until my trick got found out.
I've become multi product orientated over the years and many times can tell if something will sell well in about 10 seconds. People smarter than me sometimes blow my mind with the ideas they have but for the most part I have decent ones.
Sell whatever the he11 will make you money is my go to theory.