When they say 'You must only go shopping for essential things' I think it is ok to get other things at the same time. It would be wrong to venture outside to buy only stuff that you want for pleasure. Anyway what I have planned, is to wait until I need to collect a prescription or need the obvious things food wise when some items become low, then make sure I get other things that I need at the same time during the coming weeks/months. Things like paint, tools, garden items and anything else to keep me busy and my mind occupied. Stay safe and listen to what the authorities tell you concerning this virus.