We had friends who years ago started buying stuff, everthing from clothes to cot and bassinette before they even thought of TTC. She had most of what she wanted when they eventually got pregnant.
Me, I'd be more inclined to wait. You may buy stuff now like a cot or change table, and put it together when bub is on the way, only to find something wrong with it or something that you're not happy with and then not being able to exchange or get a refund if too much time has passed. Suppose it all depends on when you are buying and TTC. :0

Nic