How many times do you try a plant before giving up?

WAMS

Two winters, two dead alstroemeriae

 (despite a thick bark mulch as recommended each time).

Would you just assume the garden wasn't suitable for it / you weren't clever enough to look after it, or would you try again?

Thompson and Morgan have three alstros for £10 and I must say I'm tempted.

Hostafan1

I don't carry passengers. If it doesn't earn its keep: it's gone.

Uff

It depends on how much I like the plant/shrub. Twice if I really like it but after that, I admire it in other gardens. Once only if I'm not that fussed about it. 
However, if someone gives me a plant I nurse and coddle it like nothing you've seen before and if it dies I'm really upset. Apparently, I'm not on my own, other gardeners feel the same. 

AnniD

If you can spare £10 you could give it one more try, personally l'd take the hint and try something else. Right plant right place, in the words of Beth Chatto.
Sometimes, in the words of AnniD, right plant, right place, dies anyway 😁.

B3

Once.
Get something else. Alstromeria don't want to be there
Could you try something with a similar flower - day lilies?

Fairygirl

Twice at the very most, and only if I like it enough.
Life's too short to faff with things that just don't suit 

GardenerSuze

Yes move on there are so many wonderful things you could grow. Not your fault just not hardy enough for your conditions.

WAMS

Day lilies are pretty...

You're all right of course.

It was a particularly sweet pink one but at least I have my memories.🎻

Uff

. . . and £10 still in your purse @WhereAreMySecateurs

JennyJ

If I can work out why a plant might have failed and I can do something to correct it and I really like it, I might give it a second chance. Otherwise it's just throwing good money after bad.

Allotment Boy

Tricky,  if we really like it maybe 3 times. We tried with Agastache "black adder" several times because we really wanted the dark purple colour,  other paler cultivars survive better .