My two older kids especially have always had a hard time with transitions. Left to their own devices they will be found at noon, starving and cranky, still in their pyjamas and still engaged in whatever was the first thing they started doing when they rolled out of bed. They're 10 and 8.
But it does get better. They will now often allow themselves to be pried away with just a nudge or two. Gradually I find them setting their own limits and making small efforts to manage their time effectively. Hard-won progress, let me tell you, and definitely related in large part to maturity. And just in the last 2 weeks I find my 10yo doing some starkly mature time-management things. I hope it's maturity and not just a fluke.
I still sometimes resent not being able to go places, do interesting things, visit friends. I sometimes resent the time wasted on long transitions. But when I find myself disappointed by expectations that weren't realized, it's time for me and my kids to re-examine things. Invariably when we talk about it it turns out they're disappointed too. They'll complain "why do we never do anything fun?" (Well, maybe because you refused to leave your marble maze to go to gym night, and didn't want to get out of bed to go to Bob's place, and didn't manage to get your coat on in time to get to the community garden, and....
Resentment is a call to communication and problem-solving. Sometimes it's me who needs to be more realistic in my expectations. Sometimes there are things my kids need to allow them to make transitions more easily.
Here are some things we've discovered:
Mealtimes are natural transition-times. If I can get my kids to the table with a meal and some conversation, I can usually get them headed somewhere afterwards.
A rhythm to our days is a big help. Not a routine, just a gentle predictability. A dance, not a march. Things are offered, not compelled. Often the kids decline most of my offers, but I continue to make the offers every day anyway and sometimes, out of the blue, they decide to take me up on things quite consistently for a while. They seem to appreciate me acting as their sundial, subtly reminding them what time of day it is.
We talk the night before about our upcoming day. We run through the time-management stuff... what will need to get done, and when, if we're to do such-and-such. Last night I said "Tomorrow is Holly's memorial service at 2, and then you're invited to Grandma's at 7 for a sleepover. I'm busy with a rehearsal so you'll have to get dressed by 1:30 in something nice, and also get your overnight stuff packed on your own before supper. Do you think you can do that? Do you still want to go to both those things?" We write stuff on a family notice board, and my three older kids (6, 8 & 10) have watches to make it easier for them to keep track on their own. I don't expect them to manage this stuff without reminders but it helps them to have the knowledge and the tools anyway.
I am consistent in making sure the kids follow through on things where their absence will affect others. To me this is a matter of respect. Going to the park is discretionary. Going to art class is not, because the teacher buys materials for every child, and plans projects that run over 2 or 3 classes. If you commit to something like that, you go unless you have a very good reason not to. I am quite clear with my kids about this, and they know where I will give and where I will not. Occasionally I will have to say "it's okay if you don't want to participate when you get there, but we need to go, because they're expecting you." Transitions are the problem for us, not participation, so the reluctant child always enthusiastically joins in when s/he gets there.
I'm a dawdler by nature and I know that vague and remote deadlines are the worst for us slowpokes. If I catch myself saying to my kids "you need to start getting ready soon" I know we're all in trouble. Around here "start" (to get ready) and "soon" are not good words to use. "Do it" and "now" are much more effective. While my slowpoke kids benefit from warning that deadlines will be arriving, when the actual deadline is presented, it needs to be firm and immediate. If we're headed to piano lesson or art class or gymnastics and need to be out the door by 3 pm, I tell them "It's 2 o'clock. We're going to be leaving in an hour. Just so you know." At 2:55, I'll get right in their space and make eye contact and say "It's time to get ready. You need to stop what you're doing. Here is a sweatshirt. Put it on. If you don't want to wear this one, I will take you to your room and you can pick out another. Then you will need to put your shoes on and get in the car." And I will walk the child through the getting-the-shirt-and-shoes step by step and with physical guidance if necessary, never giving him the chance to wander off-task.
If you haven't been doing it this way, it may take a while until your child adjusts to the fact that there's no "wiggle room" any more. Explain to her that you've changed tactics, and why, and she'll probably get it. "When I give you half an hour to get ready and leave it up to you, you get lost along the way. So I'm going to give you five minutes, and help keep you from getting lost. That way you get more play time, and I get less aggravation. What it means, though, is that you have to come now. Understand?"
I have to say that we have remarkably little difficulty these days getting to non-discretionary appointments and activities. So maybe it does get easier.
On the other hand I still sometimes despair that my children could sweep the Olympic medals in Procrastination.