Would it be odd to buy a leaving gift for my manager?

[PolloIsChicken]

Is it weird to give your line manager a gift if they are leaving? If you've had a supportive great line manager, who has helped you a lot, and is a genuine decent person.

Not weird at all.
Is there not a general collection for them leaving anyway though?

No

No, it's a nice thing. I would give it to her in private though rather than as part of general leaving celebrations

No, why on earth would it be? I wouldnt see it as any different to anyone else that was leaving. Personally Id be more likely (and have) to contribute to a collection rather than buying something myself but if there isnt one going or you want to get something extra thats absolutely fine.

I want to privately give something small for all the support and help in the past 3 years. Maybe a box of chocolates.

Why don’t you contribute to the collection and write her a card with what you have said here. I have had cards like that in the past and they mean far more to me than gifts.

I think yes I'll get a personal card thanking her for all the help and support over the past few years. I still might get the box of chocolates.

That would be 100% appropriate.

Honestly I would just contribute to the group collection so they get enough money to get something decent.

Past few leaving stuff we've had for other colleagues there's not actually been a group collection for a gift. There's been a group card and then a leaving meal.

When I left a team member gave me a box of chocolates and a hand written note thanking me for things I hadn’t really realised - it meant such a lot to me and I still have it

I gave my old manager a gift when he left, he was brilliant and really supported/pushed me to stretch.
On the flip side, I recently had a junior leave my team and he bough me a candle to say thanks for the support.

I think I'll be doing this as well

Why don't you organise one? No use waiting for other people to do these things.

Weird if you didn't. As a manager I don't expect gifts from my team but when I left my last place my team brought me a beautiful bouquet of flowers and all signed a card and it was lovely.