i could do (semi-)automated waterchanges, if i wanted to, except for one extra tube and permanent hose that i'd need to install, but... the gravel needs vacuuming every week too, so that idea is lost on my tank.
I do still have the automated valves on the tubes, but i do not have them attached to the electricity, nor do i have the computerized timers etc. that would be nescesary.
we had a thread with a completely automated wc system lately, but the installation had some fancy valves and some maximum/minimum level sensors, that were both pretty expensive.
and the tank they used it on was a fully planted tank, that indeed didn't need gravelvacuuming.