I think it's false economy growing your own potatoes nowadays when you can wait for xmas/easter season where they sell them for 10p a kilo, I usually stock up at that time and keep them in cold place and they last for months... Till the next good offer in shops come up, than I stock up again
I do however grow all kinds of other stuff myself and I enjoy it, but not potatoes..
My grandpa used to grow them over few acres years ago and I had to go and help collect them when the harvest season started, he knew a lot about this stuff and he replanted leftover last years potatoes every time... and they turned out to be fine every time, sure some might get some disease but the bigger problems were forces of nature and pests not the ''diseases''.
Found this somewhere:
'' Before it's licenced for sale every variety of every vegetable has to be rigorously tested to ensure that the crop is identical to the seed and stays this way for at least 6 subsequent generations. ie They plant a seed, then plant the crop, then plant the crop from that and so on for 6 generations then test the final crop to ensure it's exactly the same as the original.
The whole selling of specifically produced 'seed' potatoes is just an extra 'belt and braces' guard against problems.''
So having to go actually help harvest them myself I'm not really buying in all this ''disease'' scaremongering...
If you are a large farmer and the seed potatoes are guaranteed and are rather cheap in bulk than yes It's a no brainer, however we are talking about total DIY growing where a person is buying a 1.5kg bag of seed potatoes,talking about diseases in such cases is total porkies..