Finder tab switching very slow

An update: per my last post, the solution that works for me every time is this: when I notice that switching tabs in finder is running slow, I check Activity Monitor -- and every time Finder is taking huge % of memory, so I just use the Force Quit function to relaunch the Finder. Finder relaunches with regular memory consumption, and tab switching is zippy. I have no clue what leads to Finder eating memory over time, but this solution always works for me.

Thanks, kerouacjack. I was dubious at first, but relaunching Finder has speed things up. I doubted because I have restarted the machine several dozen times and that did not work so it's surprising that the relaunch does. I will see how long it lasts and post back if and when the problem comes back.