Does anyone have experience with overcoming plumbing issues on an older property?

Does anyone have experience with overcoming plumbing issues on an older property? Has there been a successful preventative maintenance that is helped Keep the lines clear or any other magic solution y’all have come up with? I have a property that is having constant issues.

Camera the lines and look for bellies, fallen bricks and other obstructions

Have you dropped a camera in the areas you are having issues in? Most of the time we would find things like a belly in the line packed solid with grease or wipes. Or a break where the line fills with dirt and the biggest issue is always roots growing into the line. Ever heard of a “sewer snake”? It’s not a real snake it’s where the line fills up with live roots. Oleanders are the worse. Their roots are always searching for water, so the smallest leak those things will grow till not even clear water can pass. We pulled one out of a line on Las Vegas that was no less than 10 depot long- it was unbelievable. Simple message is to camera your lines because there is zero liquid or granulated products that will keep the lines clear

Jetting, but it can also damage the lines depending on what type of of material it is made of.

Ask a commercial plumber to help is best path forward.
There are five plumbing systems to consider.
Cold supply in. Corrosion or mineral scale can be a problem. Bad pressure regulators happen after decades. Poor water pressure flow most common sign.
Hot water systems. Age and mineral scale lead to warm instead of hot and poor flow as above.
In unit sanitary drains. Toilets baths sinks etc
Main accumulation drains from multiple units. Grease, debris (wet wipes), solids from kitchens are all resident in unit sourced. Clogs, slow drains, repeat site visits are almost always debris related. Chemical treatments clear grease. Nothing clears wet wipes.
Venting for units. Designed well or not. You would be surprised what rodents can get into and clog up.

Repiping