Deciding to or not to weather is not a big deal. There's a couple of different approaches. There are those modellers who build to the pristine. That is, they want to show their model as it had looked brand new. There are those who want to show a model as it would look on an average day. The level of weathering goes all the way to showing their model as if it had been destroyed. A good comparative example would be someone who is modelling a hot rod model, who wants everything to shine and someone who is modelling the Titanic as she sits on the ocean's floor, argueably just about the most weathering you can do to a model.
For model ships, it is my opinion that weathering is a must. Period ships especially. These ships took years to build. The ship would take daily wear and tear while being built. Wood bleaches in the sun, splits, etc. Paint in those days faded rather quickly....you get the idea.
I am in two builds right now. The first is Heller's Soleil Royale. I have just started rigging her shrouds. I've done and am doing only enough weathering to show detail. In this case, too much weathering would detract from the beautiful guilding on the model. Examples would be the dark wash that I've put on all gun carriages, followed by enough drybrushing to make details stand out. The same for the deck, masts, and whatnot. What I'm not doing is rust lines or hull damage from prolonged exposure to seawater. What I will end up with is a model that has a bit of an "antique" look to it. I don't intend for this to be a scale model. There are too many flaws, both in the model's design (which has been discussed extensively on this forum) and the admitted flaws in my own skill as a modeller. No, this is going to be a show-piece in the living room (everyone thank my wife, who relented and is letting me put it in the living room).
The second build I have just begun. Revell's 1:96 Constitution. This kit I intend to do a little more weathering with. There will be worn egdes on painted wood in logical areas, as well as wear-marks where ropes drag repeatedly across wood. It won't be all over the model. Just enough to make it look "lived in." I will also be weathering the copper hull. On models, pristine copper hulls just don't look right to me. My intention is to try and give an idea of Constitution as she would have looked on an average day at sea in the early 1800's. Not in before, during, or after battle, but just your average day at sea.
And weathering is not just all about washes, chips, and drybrushes. Weathering is also about a deck that has some planks lighter shades, indicating repairs. Weathering is coils of rope piled here or there on deck. Doing historical searches, reading Captain's logs, old pictures...just about any research will give you a wealth of ideas for "weathering" your ship.
It comes down to what you want. There is no rule about weathering. Just look at your model and decide for yourself. And have fun building. That's what it's all about.
Grymm