Need help! House in Seattle, old pipes started to cause problems. Frequent clogs appear, and sometimes the water flows slower than usual. I want quality service and professional diagnostics. Can anyone suggest something?

Be sure to choose companies with experience working with older homes. Modern diagnostic methods can make it much easier to find the problem.

Check out https://bens.plumbing/services/hvac/mini-splits/ . This company specializes in sewer line repair in Seattle and offers video inspection, which is especially useful for diagnosing old pipes.