We usually always anchor out alone, but when we have anchored in the vicinity of others I for sure try and exceed the length of the rode since boats won't swing the same always. Our small boat sails on anchor a lot and if we were near another boat sailing on anchor we could sail into each other. Generally speaking you are right they will tend to move in the same direction with wind and tide changes.
Try and find out how those near you are anchored, one anchor, Bahamian Moor, etc.. We anchored in close one place in Florida and...
... put two anchors down to avoid moving into shallow water in one direction and into the path of boats going in and out of a marina in another. We basically held position regardless of wind and tide. We were alone until ...
... a cat anchored very close to us on one anchor. I called over and told them that we had two anchors down and weren't moving and that they might swing into us on a wind change (the wind was forcing them away from us at that moment). They then moved further away.
Another advantage to trying to give yourself some room is what if they or you drag a little. We have only dragged on anchor once about 20 feet, but we have good gear and usually have more scope down than recommended and often use 2 anchors.
I love anchoring and the challenges it presents in different situations. I don't enjoy anchoring near others in a crowded situation,
Our 37 Endeavour --- Our 26 MacGregor --- Trips With Both