How can I weigh how useful a specific frequency that a network provides is?

I looked up the [T-Mobile frequency chart](https://support.t-mobile.com/docs/DOC-4988) , 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](https://www.amazon.com/Huawei-P20-Single-SIM-Unlocked-Smartphone/dp/B07CGCG23Q?SubscriptionId=AKIAJIYNF643F4NAP3YA&tag=i0914a-20&linkCode=xm2&camp=2025&creative=165953&creativeASIN=B07CGCG23Q&ascsubtag=06-3647101-05-3674249) . 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](https://en.wikipedia.org/wiki/Samsung_Galaxy_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?