I flew a Robin a few weeks ago with no suction (so very sluggish AI and no DI). We were only going for a VFR bimble to the Isle of Wight and back to Bournemouth - if I hadn't accepted the aircraft my father would have had a wasted trip down from Leeds (no other aircraft available). However I was mindful not to get blind 'press-on-itis' but to carefully consider the 'risks'. It was a lovely day and I know the area well, just look out the window and use the compass if necessary. I guess it was my first real 'command' decision, but I wouldn't have gone if there was any chance of inadvertent entry into IMC as I have never done partial panel.