Hardly ever. I have three NES toasters, but none work at the moment. Pretty sure all three need new cart connectors, but i have never changed one out. Need to do that this year. I have a top loader as well, but usually dont dig that out. I still have one of those NES/SNES clones out near a tv, but havent used it in years. I bought the fc mobile II and have played originals on that just to see if they work or not. Same with the SNES. I have the Supaboy and the RDP2. I guess i could test the NES on the RDP, but that adapter is ridiculous.
Mostly, i emulate out of convience. Plus, I can take the emulation to work with me to play on breaks. Still collect the originals, but until I have a dedicated game room, I usually dont play them.