More than once it has suggested i get of the motorway, go through a city centre, because of slow moving traffic on the motorway, i never do this as i know the city is just as congested, and when i drive past the exit it wants me to take it just wants me to stay on the motorway and says that i will now arrive 2 minutes later.
So the whole "Do not reroute if i save less than 15 minutes" is a bit iffy and atleast in the country i live in, it has to be really bad on the motorway to warrant getting of it.
My daughter lives on one side of our city, I live just outside the city centre on the other side. If I head home past 2:30 (before Covid it was 3:00 p.m.) I'll hit slowdowns. There's an electronic sign on her side of the city giving me estimated length of time to my exit which will be between 4 minutes (Christmas day in the middle of the day!) and 38 minutes is my personal worst but someone posted a photo of it a few weeks ago showing 59 minutes.
Remember I don't use NoA or FSDb, the car won't make any changes without me initiating them so the NAV is just one input (the sign another, radio traffic reports a third, driving conditions the fourth) in my decision making. (I choose to drive my car rather than have it drive me.) In theory, the time for the driveway-to-driveway trip should be 22 - 24 minutes so I pay attention to the sign and then consult my NAV to see if it wants to reroute me through the city centre, or, if things are really slow, through another province since I live on a border. There are times it reroutes me through the centre, and times it keeps me on the highway. I'm set to 'Do not reroute if I save less than 10 minutes.'.
Even if it does recommend a reroute, I have to get across two bodies of water before I can reroute (otherwise, I have to reroute well out of my way to get to bridges and if rerouting through the other province, crossing a third bridge to get back to my province.) So, while stuck on the highway waiting to get across bodies of water, I have lots of time to decide which route I'll take.
What I get from
premium connectivity (to bring my post back on topic) is the use of colour on the map since it does give me a good sense of how bad the trip will be (from red, to deeper red, to deep maroon) and at a glance how bad any alternatives will be. Remember, even without premium connectivity, the car will make rerouting suggestions, you just don't see why it is doing so.
As others have pointed out, using one's phone as a hotspot is a work around and if one is already paying for a decent data plan, not a bad one. (I'm all about 'the pennies' and while people say one shouldn't whine about the price of premium connectivity, the reason I can afford a tesla now is because I've spent 50 years making frugal spending decisions.) My frugality and the cost of cell phone data in my country up until recently, combined with my older mid-range phone makes this option less attractive than the turn-key subscription (which, rumour has it, will get even cheaper in the near future as our country should be getting the option to pay annually.) The subscription also means I do not have to trigger my phone to open a hotspot and connect my car to it, open the mapping software to run every time I get in the car, and turn on voice command for the phone. (I understand I could probably set up an automation for that, but don't bother since with premium connectivity I don't have to think or plan, I get into the car and that part of the tesla just works (or doesn't since there are vast parts of my country, even withing 40km of city centre, with dodgy LTE service.)
That plus (along with the ability to use Tune-in to find local radio stations when on the road, or local radio stations when there is a significant news event - we listened to the Jan 6 riot coverage over DC's NPR station) makes Premium Connectivity an expense I'm happy with.
Even without Premium Connectivity, the tesla's access to live info to calculate routing and travel time is much better than my previous car with an outdated NAV system that didn't give me any accuracy when there was traffic.
The downside with the system is it doesn't take into consideration the driver's profile. This is always subject to change with an OTA although this would likely be a holiday one since it is just a bonus improvement. For me, it is usually consistently roughly 5 minutes shy of my actual time, not due to changes in route traffic but because I don't drive much above the speed limit. I have no idea how much above the speed limit it is figuring the car will travel but yesterday (a holiday and mid day so no traffic whatsoever and a bright sunny day) I texted my friend to give her my arrival time according to the car and then pushed the speed limit 10 - 15% the whole 30 KM highway drive. I was still 3 minutes later than the time originally projected despite there being no confounding factors (and only two traffic lights on the whole route. It seems to me that it should be able to look at the driver profile and since I'm set to Chill and have a history of going near the speed limit and not weaving in and out of traffic, it should know to pad the time estimate a bit compared to the average tesla driver.
Yesterday, in particular, as the car had a much longer drive after I was using it, and it was -9C out, on my way home I was back to my slower driving in order to preserve range for the next drive (and heat was off in both directions, I just used the seat heaters.) The 212km total driving for the day used up 71% of our battery, just in case anyone in interested in why I tend to not speed - winter range hit from winter tires and cold is significant and distances in Canada large and SC locations much fewer than in the US, so that's why I keep our standby charge in winter at 85%, but ran it up to 95% before leaving yesterday. Then again, as I said, I'm frugal, so not speeding is a life-long habit to lower fuel costs and avoid speeding tickets, the lifetime fuel usage on my previous car was 5.2L/100km (46mpg for US folks.) I didn't buy a tesla to save money on gas, I will likely never break even if that was my criteria for purchase.