Trying without buying
To avoid getting committed to a contract and later regretting it you can try dongle and mifi without commitment. My comments here relate to 3G, possibly 4G is similar.
Dongle - simply buy a PAYG pay-as-you-go dongle. This lets you buy small chunks of data (use within 30 days) with no further commitment. Alway useful to have because it works anywhere.
MiFi - get the one month rolling contract. This can be cancelled on a month's notice, so you are only committed to a couple of months. If you decide to cancel, you can keep the device and put in a PAYG sim card, perfectly legal, and then use like the payg dongle whenever you wish. Again useful if you are away from home, the MiFi creates a little bubble of wifi for your laptop, tablet or whatever.
Cost is about thirty quid to get started and about fifteen per month for 3GB.