Our landscaper suggested that we get our own mower for the maintenance guys will use. When a mower goes from property to property, it tends to carry weed seeds with it, and that is how lawns most often get weeds.
Our lawn is a a hybrid Bermuda type, with a fescue overlay. What this means is that it is a combination of two types of grass. The hybrid Bermuda will thrive in the heat of summer, and the fescue will do better in the winter months.
But Bermuda grass needs a reel mower, the type with the large spinning chopper in the front. Compared to regular mowers (around $300), reel mowers are expensive (around $1,200).
However, we happened to find this beauty of a dinosaur for $150 on Criaglist.
We contacted the maker, McLane, and were able to get a front throw basket and a manual, and had it tuned up at our local mower shop; it works fine.
Now the landscape maintenance crew uses this mower every week and hopefully our lawn will remain weed free.