Is this a friendship?

Seven or eight years is long enough that you'd expect some kind of shape to have formed, I think, and yet from what you're describing it sounds like it never quite has, which must make it hard to know what you're actually dealing with. The watch after thirty minutes would stay with me more than the long gaps, because there's something a bit deflating about someone who greets you warmly and then is mentally out the door before the coffee's finished.

I had something a bit similar when my book group folded, not exactly the same, but the friend I'd been closest to in it eventually moved away and the contact shifted into something that looked like friendship from the outside and felt thinner from the inside. I kept going for a while, partly out of habit, before I gradually became less available. I'm not sure she noticed much, which probably tells its own story.

The "used" feeling you mention is worth paying attention to, I suppose, even if she probably doesn't think of it that way. It might just be that her life has moved in a direction that doesn't leave much room for local friendships, and you're a welcome familiar face when she passes through, and she genuinely does like you, but those things can all be true without it being a friendship in the way you mean it...

If the next meetup is convenient to you see her. if she's become very tiring to you because the conversation is one sided then call it a day.

This is called life, the people we knew 60 years ago we keep in touch with most of the ones who are still living just the occasional email and Christmas card.
My husband and I both have social lives with separate interests and we go out together. I'm still socialising coffee and a cake with new people, so life is good.
Don't concern yourself about things that were or should be just get on with life because it can be short.

I don’t think I’d carry this friendship on to be honest, I would find it really rude if my friend would abruptly look at her watch and say she’s got to go, to me that would seem that she’s only interested in talking about herself and not really on your wavelength I’d knock it on the head but not literally 🤣

You just might be the only attempt at a friendship that she has. Your life may feel boring to you at times but it is a stability that she will never have and though she is a busy lady, I think she cherishes the time you give her.

You say you're not sure why she wants to keep in touch - the question you should be asking is why do you want to keep in touch. You have other friends and aquaintances so why do you need her in your life? You obviously find her tales of travel boring, you say she's not interested in you, why do you still meet?

It's really up to you. Do you enjoy meeting her, even though it can be one sided with the chat?
Just suit yourself.

Aveline

Just go with the flow. Enjoy her flying visits and don't expect too much of her.

I agree with Aveline.

There's no need to lie to a friend .
I was really shaken the first time I realised that my friend was lying to me .
I began to wonder what other lies she'd told me .
My trust seemed to evaporate.

Telling lies is a massive red flag for me. I once caught a 'friend' out in a lie and never felt the same about her again.

Sounds like the relationship that I have with a long - term friend of 25 years plus.
She blows hot and cold and over the last three years - it's become extreme.

I've gone through a lengthy period of feeling really let down and upset - now I realise that she's totally self engrossed and only does things,which please her .
I've also found that she tells some real whoppers and can be dishonest.

Recently,she's been all chummy again after months of being rude and unfriendly.

I've learnt to just step back.
There's no need for heated words /not speaking .

I plan to eventually move away ,anyway .
I'm sad of course .
It's just life.

TBH I think that I wouldn't bother with her. As I've become older, I've less time for people who aren't real friends. These days I prefer to meet up with people who have time for me. This said, we are all different, so perhaps seeing this person suits you, Stillness? If it really doesn't, then why bother?

Stillness.., You really must stop feeling resentful. Things happen in life. Do what I do, just look forward to your friends next visit.

Sounds a bit like my best friend that was!. Her DH died and she’s got a new man in her life. She’s having a wonderful time, here there and everywhere, it’s almost non stop. I can’t keep up with it all and I miss her🥲.
You think you know your best friend of 25 years very well but you don’t really.
There was never a hint that she would be interested in finding a new man so it came as a terrible shock when she did. I just got chucked on the sideline or that’s how it feels like.
It’s taken 3 years for it to sink in that she’s not going to be around much anymore so I’m getting on with my life. Hers is much more exciting and I wish her well as she spent years looking after her DH extremely well who had Alzheimer’s.

Aveline

Just go with the flow. Enjoy her flying visits and don't expect too much of her.

Yes I agree, if this is what you want, if not just back off

Personally, if you’re not offended by her, I’d just meet up with her if it’s only a few times a year, but you could always be unavailable now and again and see how it goes?

Mismatch of energy. You like a friendship with a bit more to it. She is one of these people that flits everywhere. We had one at our WI a few weeks ago. She was very bubbly, everywhere, full of energy, didn't stop talking and 'Woosh' she was gone. I left the outing thinking 'thank goodness I am not friends with her'.
Focus on the people who are worth your time and energy. You could always treat her as a very superficial contact letting her do all the contacting and arranging. But, up to you what you want. And, remember, you are worthy of good friends.

She is no longer "great buddy" material. Back off slowly and put your energies into more rewarding relationships.

There is that wise saying about relationships:

"The popular phrase, often attributed to a poem by Brian A. "Drew" Chalker,

suggests that people enter our lives for a reason, a season, or a lifetime

This philosophy emphasizes accepting the impermanence of relationships, encouraging gratitude for the growth or support a person brought, rather than harboring resentment when they leave.

so maybe its was a season or a reason.

Just go with the flow. Enjoy her flying visits and don't expect too much of her.

I would just slowly back away. Don’t be available when the next meeting is due. Find other things to interest you. Maybe learn a new hobby or go out with other friends. I had a “friend” like that and everyone around said that we just weren’t suited to each other. It took me a few years to see it and I am a happier person with her not in my life. Take care.

You’ve outgrown each other, it happens.