Americans have a lot more access (especially in urban or suburban areas) to various choices regarding things like this. Ireland and Europe vary a lot. From the Germans who like their fresh, non-GMO foods, which is probably one reason despite their love of sausages and other treats, like the Danes (who by law, have to cook most "fast" food with butter, not seed oils) are healthier than the average Americans to rural Ireland, which might have some avocado oil in a tiny bottle for twenty dollars hidden somewhere, if you can find it at all. The internet has improved things, but many things are not affordable unless you don't use them much.
For several reasons, the last three years have had terrible Olive Oil shortages and price spikes. My housemate did stock up, but I finally had to tell her ONLY to buy extra virgin. She is very price-conscious and didn't see the point. I finally said, "It is better for me, and that is what I want to use." In practice, I use the store brand (which may be illegally mixed with other oils) to grease pans or cook with Extra Virgin for eating directly (like drizzled onto tomatoes). There are different thoughts on how much damage olive oil suffers when heated, but it is still probably better than seed oils.
I use the seed oils the two or three times a year I deep fry, or, as I said, in small amounts (one fluffy loaf of bread a month, or greasing pans that need a high-heat-tolerant oil). At least over here, they are not GMO.
Some things we used to be able to get, like Beef Tallow, went away about twenty years ago. When the generation they grew up with died off. My housemate is primarily vegetarian (she will eat fish, but I have allergies), so cooking or baking with lard/tallow is off the menu - she can taste it. If she can't taste it, she doesn't care; it isn't a moral thing with her. But she can; we've experimented. I haven't seen "light" olive oil in the shops for at least a decade. We did have some when it was a big fad to bake with in the US.
Also, beef tallow and lard are hard to get these days. I have made it at home, but they also flavor things in an unfortunate way. I suspect industrial products can be refined better.
Finally, I always keep a couple of large cans of supposedly non-trans fat shortening (like I believe) for emergencies. To get us through a crises while things sort themselves out - also on rare occasions to make pie crust - though I suck at that with either shortening or butter. I was horrified when I discovered Nightwolf was using my old 1950s recipe books to bake with but using the shortening option instead of butter. He said,"I'm just following the recipe," and I said, "That's because they used to think that butter was bad for you, and shortening was supposed to be better for you and cheaper." I told him that shortening was a prep, to be used only occasionally for unique things like his molasses cookies that didn't snap without it (he hated them with lard, I tried) or shipping lanes breaking down. We needed backup sources of oil until things sorted out.
Anyway, one thing I always say is to study how people lived and preserved food traditionally in your area. What works great in dry Arizona doesn't work in humid and wet Ireland.
