If they have no outages reported in the area and you’re the only one down they will send a tech to test the fiber or copper line that feeds your home. If they find the line is good then the rest of it is on you and they’ll likely charge for the techs time that did the test. They should provide a certified result of their fiber or copper line test though.

We have to deal with this all the time at our data centers. Even with in house techs that can test and tell us the fiber is down likely due to a line being cut by the construction crew 100ft away, the ISP will still send their tech to find the exact same results before they send out a repair crew.

Well yeah each service provider is only going to troubleshoot to the end of the equipment they are responsible for. For water that means your water meter, for for power your power meter, for ISP it means the outside line demarcation point where it turns into your equipment.

If they own the ONT modem/router they can troubleshoot to that point. If you provide your own all they can do is send a tech to make sure their signal is active and if it is they’ll charge you. If you use their equipment they’ll troubleshoot it and assume that the issue isn’t a simple layer 1 issue, and if it is will.sometimes eat the cost on a quick repair if it means keeping you subscribed and happily paying equipment fees each month.

Only thing I’d disagree with is they’ll update it when it needs it. They may never update the firmware on their equipment at your place even if has major security flaws. They’ll also have no problem upgrading your plan to 500mb speed meanwhile your decade old modem/router only has a 100mb NIC. They’ll for sure do the least they can, but that may still be more than certain customers are capable of.