It can be a real pain. I rarely ride any one of my bikes more than once a week. In fact, I haven't ridden any as yet this year. My A10 is the worst for wet sumping - half the tank in the sump in a week. Trying to start it with the sump half full of oil is difficult due to drag on the crankshaft slowing it down below reliable spark levels with the kickstart. And if it does start, then oil pours out of the engine breather making an almighty mess. So far I've been draining it before every ride. I have a sump plate with drain plug, but even then it's an annoyance. Being fairly tidily dressed ready for a ride is not the best time to find a drain tray and clean it, get a spanner, get on one's knees to drain the oil and then proceed to filter it back into the oil tank. I got so fed up with this I've fitted a valve in the oil delivery pipe. I appreciate there's always the risk I could forget to turn it on, but as I always check return to tank on my bikes before setting off, hopefully I'd catch my mistake in time. I realise there are options for connecting a valve to the magneto, but couldn't be bothered with the extra work. To me, the risk outweigs the frustration it was causing me.