Sewer trouble here usually comes down to two things — old pipe in the established neighbourhoods, and ground that moves.
Roots in the older streets
Riverland Terrace, Harbor View and the surrounding streets have clay and cast iron lines with mature oaks overhead. The joints weep slightly, roots find them, and once inside they catch everything passing. Cutting them clears the line for a season; lining removes the joints they are getting in through.
Soft ground and sagging pipe
This is the James Island problem. Wet, soft soil and a high water table mean pipes settle and shift more than they would on firmer ground. A section sags, holds water, and starts collecting waste. That is a repair to one part rather than the whole line, and only a camera tells you which you have.
Backups that come and go with the tide
If your drains behave worse at certain times of day, that is worth mentioning. It usually means groundwater is getting into the line, and it is useful information rather than a coincidence.
Ask to see the footage
Roots, a sagging section, a crack and a collapse cost very different amounts to fix. You should be able to see the problem you are paying to solve.