I too don't tot it up.
My aim is to grow veg which has the best possible flavour (so poor yield, disease prone [up to a point!] and "fussy" are all fine, provided they taste fantastic
, and no chemicals at all - I very very rarely relax that, the whole crop has to be at risk, and I can't remember the last time in 7 years on this plot that I have used anything [other than fertiliser and some slug pellets]).
Bit hard to get solutions to either of those at the Supermarket, so I figure there is no direct price comparison and thus absolutely no justification is required!!
This year I have started growing through Mypex / Weed suppressing membrane. I made that decision when about 25% was already planted, so the later 75% has been done that way. A fair amount of extra time was spent cutting "X" slots for each plant-position in the Mypex (individual pieces, one-per-crop, labelled to be reused in future years, and with a bit of extra length in case I want to plant a-few-more of something in future years, any excess rolled up otherwise). That apart, there was some increased time spent at planting, as its a bit more fiddly than just "slamming them in", but I figure that next year the Mypex will be down long before the crop is planted, so I won't have to spend time hoeing the weeds off, so that will compensate for a bit more time planting-out.
Upside, from this year, is that I have done far less watering (long term goal is to put some leaky hose under the Mypex at planting time), and pretty much zero time spent weeding where the Mypex was in place (some weeds still poke through the "X" where a plant is planted, but little compared to having to weed the whole bed).
A gardening mate, also a newbie to Mypex-ing the whole plot
, and I think, subjectively, that yields are better.
I'm not planning on using it for some crops (I figure harvesting Parsnips, through Mypex, will be a nightmare), and I'm not too sure about very closely planted crops, like Onions or Garlic, but my mate is going to do it for everything!