Limiting your fertilizer to once per year means you are limiting the performance of your lawn and in some cases to its detriment. In MA a good rule of thumb is fertilize 4 times a year, memorial day, labor day, around Halloween, and around Thanksgiving. If you don't like the idea of using synthetic fertilizer you can use organics and fertilize more often. Cool season grasses need 2-5 lbs of nitrogen (it depends on the type of grass) per 1000 square feet per year to be at their best. If you are going to do the November feeding it's best to use a synthetic quick acting nitrogen (urea, ammonium nitrate) when top growth has stopped. Weed and feed is not recommended for a number of reasons, don't waste your money on it. It's better to fertilize in the spring (memorial day), then a week or two later kill the weeds with selective herbicides that you apply to just the weeds, not the whole lawn (unless you have a large weed problem). It's too late for a preemergent now to suppress poa annua, but it would be a good idea in the spring to suppress crabgrass and other spring/summer germinating weeds.

A weed and feed now will certainly help. I recommend a winterizer to be applied after the top growth slows down.

Over the years of reading and writing in lawn forums, the record for weed and feed is terrible. Every year we get questions from homeowners wondering why they still have weeds after using weed and feed. Tiemco didn't get into it and I'm not going into it either, but the problem is the application of both products at the same time. If you want to do your one app of fertilizer now, then come in with a good weed killer spray like weed b gone a full 2 weeks after fertilizing. Spot spray each weed with wbg and you'll be much happier with the results.

The fact that you have crabgrass indicates you are probably watering too often and mowing too low. You might change your care program and you'll see fewer weeds without the use of herbicides.

Why do you only use one app of fertilizer per year? It is a budget issue or time or because you just have not seen any benefit from fertilizer at all? I was in the last camp. Synthetic fertilizer had stopped doing anything at all for me. Then I switched to organic fertilizer and everything changed. I now have an incredible lawn...at least compared to what I had before. I certainly know people with much more incredible lawns but I'm talking about the improvement.