Good Wi-Fi is about coverage, not just speed. A mesh system uses multiple nodes to kill dead zones so you can actually use the internet you pay for. If you buy a high-end kit now, it should last five to seven years before the tech feels old.
Don't chase the newest Wi-Fi 7 models unless you have a dozen brand-new devices. Last year's top-tier Wi-Fi 6E mesh systems are the sweet spot for most of us. They get cheaper every time a newer version launches. We can use that cycle to get a better deal.
The 18-month window is a hard deadline, not free money. If you still owe a balance when it ends, you will start paying the standard interest rate on whatever is left.