I always say "cocktails at 5, dinner at 6" so people know there's a cushion. We also entertain families with little ones, so I get it.
Otherwise, it really depends on the recipe. For dinner parties, I try to make dishes that come out of the oven onto the table with minimal fuss, so I put it in the oven x minutes before it's time to eat, with 5 minutes to cool or set/rest a bit. I don't tend to do stews, crockpot dishes, etc., with guests, although we eat those a lot during the week. Feels too casual!
Our microwave also has a keep warm feature and a shelf that can be used to stack dishes like sides that wouldn't be ruined by nuking for a while (mashed potatoes, etc.). Anything that cooks in a Dutch oven would stay quite warm for a while, too.