Every so often I can make it happen, but most times I'm struggling regardless of how much prep time I give myself. Feel like it might be related to ADHD? Either way, I'm so bad at it 
It's the old ADHD joke: What kind of ADHD are you? Are you always five minutes late or 30 minutes early?
I did for a while. I have got it down to a tolerable rate by accounting for transitions. Like it doesn't take me zero minutes to go from being inside my apartment to sitting in my car or bike, that takes time. Getting out of the parking garage and onto the road takes time. Parking or finding a place to lock up my bike at the destination then walking in takes time, more time if I have to find an office in a large building or campus. All these little transitions easily add up to 10-15 minutes that you have to append onto whatever google maps is telling you. There's this weird psychological barrier where I didn't want to believe that it took me that long to get somewhere end-to-end, that it would take 45 minutes all told to get to class on time instead of 30 minutes. But that was the reality.
that's a good tactic. I time things sometimes, like transit time (walking, driving, etc) or how long various "processes" associated with getting ready take. I kinda make a game of it socially and I'll text someone I'm meeting with like "knocking on the door in 12 minutes" instead of saying "10" or "15", then I'll check the timestamp when I actually see them to see how close I got.
it's all in service of not having to rush or even feeling rushed under higher stakes circumstances, so I can be more present where I am and mindful in my interactions even surrounding big events. I miss out on a lot when I'm feeling rushed, personally and professionally.
I used to work for a guy who was late to everything. always. as a rule. it was a power play. he was amused that others would be kind of stuck waiting on him to arrive somewhere and he could always spin it as being a casual guy with "a lot" going on. the evidence for this was always, "I have people waiting on me". like he had no agency in creating any of it by telling people when to be somewhere and then not being there.
he had a lot of institutional power, so there was no course correction for him. but those of us in his orbit all had a shorthand for it and would express solidarity. until his throne went away. he was very hurt that no one wanted to invest much in maintaining a social relationship with him after that, though all of us once caught in his bullshit have stayed close with each other even after over a decade with thousands of miles between us.
he grew up rich around other rich people, so he never learned what it was like to be stuck waiting for someone else.
i am neurotically on time and will actively apologize multiple times whenever i'm late but i seem to only be friends with late people
I was born with the ASD time management(look the place's hours up ahead of time, check map drive time, have gas in car day before, etc) and my wife was born with the ADHD time management(pure fucking chaos). It's probably what most of our disagreements stem from.
I'm actually on of those never-late, super dependable types. Growing up, Dad was always dragging his feet and showing up to stuff late, and the stress of that whole process made me very good at always arriving on time.
My big problem is that everything takes longer than I expect it to. This sucks when I work in a field where you have to make time estimates all the time.
I'm either 30 minutes early or 20 minutes late for everything with no inbetween
I'm usually late for everything and have been that way for as long as I can remember. Has caused some problems for me in the past tooI am never on time. I’ll be either 10-30 minutes late and I will provide no excuse or explanation.
If I’m early, that is my time, and I will utilize my time until I am again 10-30 minutes late.
Yeah, I spent most of my career on "improvement plans" for being late to work. Luckily it's an industry where that's not uncommon so I was able to do better for a little while and shed the "late guy" persona and got into a salaried (no clock in) role where I come in ahead of my management anyways so I feel pretty comfortable. I do often end up staying late for similar reasons (very poor time management).
I'm the exact opposite, even thought of being one minute late or something will stress me out.
Been this way since childhood. Used to get detention/paddled for being late (I'm a child what am I supposed to do drive the car myself at 8 years old?)
Always late to jobs despite leaving what I perceive to be enough time to get there. A lot of places let me slide since I was a good worker.
I don't know, at this point in my life I don't think I can change it.
Punctuality is white supremacy and I will not elaborate.
