If you're worried about IO, then yes - although I don't know how real that worry should be. Most will only get written when changes are made, and the timestamp on any file will tell you when that was... my suspicion will be "a while ago".
If you have swap, /tmp or IO devices (/dev) on SSD then I think tvheadend's little overhead will be negligible by comparison. I suspect filesystem type/TRIM support, swappiness, cahe policy and similar would be greater considerations. My HTPCs run off SSD, but my server is mechanical HDD through-and-through.
Maybe iotop or sar can give you an insight into what processes are writing, when and how much?