Newbie Question: How important is it to match the size of the liner to the wire size?

I note that there are several different sizes of gun liners for my new MM180. Is it important to match the liner/wire sizes, or is it not normally a problem. Reason for asking is that up to now I've only used .035 and .030 wire in the stock (.035?) liner without seeing any problems. Shortly I'm going to be running some .023. Can I expect kinks, jams, erratic feed, etc. if I don't buy and install the smaller diameter liner?