Why bulk buying is that frugal if you're single

So one mistake I made when I was first getting into budgeting/frugal living was to bulk buy. I read so many blogs that promoted this method of saving food money that I became super eager and would always look out for bargains, I didn't consider that these blogs were written by mothers and couples, not by single people. For me it was a waste of money to buy a 2kg bag of potatoes for only $3 or the 2 for 1 carton of milk or the 1.7kg bottle of sundried tomatoes because I could never use them before they spoilt. I'd end up with a half full mouldy pile of tomatoes, sour milk and my 1.7kg bottle of sundried tomotaoes? I've only used 1 quarter in 3 months and they're starting to get a funky smell.

I'm not saying bulk buying is bad for single people but I'm saying its not the be all or the end all of frugal living. I buy in bulk my non perishables like flour, sugar, tea, UHT milk, canned goods. I have considered buying beans and brown rice but I don't think I could finish the rice before it spoiled and I'd probably get bored of the bulk beans and push them to the back of the cupboard. For fruit and vegies I go to the prahran markets or Queen vic markets and try to only buy what I need. This for me is living frugally and within my means.