A lot of home inspectors seem to jump to the conclusion that, just because there is a mature tree on the property, that it’s a reason to scope the drains and be sure that there are no issues.
I don’t agree.
Why fix what isn’t broken?
If you’re feeling perfectly healthy, do you ask your doctor to order you a full body scan, extensive blood work, or radiographs? No.
There are risks inherent with scoping. You could damage the existing drain, costing you a lot more. If there’s a issue with your main building drain, then consider it. But exhaust your cheaper options first.