No, this isn’t a cast iron thing. Using stainless pans, you can get nonstick effects that, in my experience, far outperform Teflon anyway. The process is called “spot seasoning.” I have cooked crispy, cheesy rice noodles with eggs with zero sticking.
I love my cast iron pans, but stainless is my daily go-to. Added bonus: use 100% copper wool to clean your stainless pan. The copper-coated wool at most grocery stores is problematic; you might get a few uses out of the coated garbage and then it starts shedding metal bits.
I went for a cheapish knife, like £20 or so each for a few knives. My thinking was I don’t want the 20 knives in a set for £19.99 that are probably made of stamped aluminium and hollow plastic handles, but by £20 you are getting something good without spending a silly amount of money.
As for the cast iron I won’t deliberately leave mine to rust, but happily use it over a fire and then just wipe off the worst of the soot/ash. But it’s black anyway so no one is going to notice spot buildup. Just remove anything that would easily brush off on other things.