Our sewer line from the house to the tank keeps clogging, roughly twice a year

Trying to sort out a dispute. Our sewer line from the house to the tank keeps clogging, roughly twice a year. One company told us it's roots and wants to dig, another says it just needs cleaning periodically and that digging is overkill. Both sound plausible and they can't both be right. How do you tell which situation you're in without just trusting whoever talked to you last? The costs quoted are pretty different too, so it's not a small decision either way. I'd like some way to actually verify what's going on rather than picking whichever explanation sounds more convincing on the day.

You get a camera in the line. That converts the argument into a picture: either you see root intrusion at a joint or you see a belly or buildup. Anyone recommending excavation without having looked inside first is guessing. We were in the same spot and had Rock Solid run their Septic Services diagnostics on the line before deciding anything, and the footage settled it in about ten minutes. Twice a year is frequent enough that repeated cleaning does add up, so if it is roots, the dig may genuinely be the cheaper path over five years. Ask for the footage afterward as well, you'll want it if you end up getting a second quote on the repair.