Dell sends out a technician to come to your house the next day to replace parts right at your kitchen table. Pretty sure Lenovo does too.
I have a high end Dell Precision 7670 with their top NBD support option. The machine has been a shit show. Dell had no parts for it when it failed and took a week to find one. The NBD support doesn't always turn up on the NBD. It's more 2-3 days, if you are lucky.
Lenovo are even worse.
I had my XPS fans replaced just last month, in my living room, for free.
(UK)