I learned to avoid draining more than one thing at a time, so as to minimise the potential for making any really careless mistakes - for example, such as (say) in refilling the drained engine oil with transmission oil or brake fluid.
With family/children around there can sometimes be many distractions, on top of which I can become very absent-minded sometimes when performing longer mundane tasks. My body sort of goes into automatic mode and my thoughts can become far removed from whatever I am doing and time ceases to exist for me. When that happens, it can give me quite a shock when I come back to reality a few hours later.