How can I weigh how useful a specific frequency that a network provides is? I looked up the T-Mobile frequency chart,

Frequency bands

1900 MHz              2    4G LTE; 4G (HSPA+); 3G (UMTS/HSPA); 2G (GSM/GPRS/EDGE)

1700/2100 MHz (AWS)   4    4G LTE; 4G (HSPA+); 3G (UMTS/HSPA)
                      66   4G LTE

850 MHz               5    4G LTE

700 MHz               12   4G LTE
600 MHz               71   4G LTE


I'm evaluating a phone, the Huawei P20 Pro 128GB. This phone isn't sold by T-Mobile but it seems to mostly support the bands, however it's lacking support for Band 71.


How much service-degradation can I expect from lacking a specific band?
Is there any way to weigh the importance of those bands individually?


Making me even more curious, I'm currently using a Samsung S5 which was sold to me by T-Mobile, and it doesn't support 600 MHz -- maybe I'm missing out on a lot, maybe the 600 MHz band isn't actually used anywhere?
It is Mobile Service Provider Specific..

Some service providers May use the frequency and Others may not... It is usually Added so the device can be used with Many Service Providers.

In relation to Missing Out..
The Lower the Frequency, The Further it travels but also the Slower the internet..

The 600Mhz range is most likely Added for Rural area's that get little reception, the speed of the 600Mhz range is a lot Slower than the 800Mhz range, However 800Mhz will Not Travel as Far...

You ultimately are only loosing out on a Slow connection, but also one that travels further..

You will drop in and out of reception slightly More than a device that does support it !