My answer is definitely 'sometimes to see' but the problem on my boat is that when sailing closehauled the hood will not swing past the boom. You have to do a big ease of the mainsheet for it to clear. Is this common ?
Almost never. It mostly stays up permanently, until we have to motor for long periods.
Then, we find that it causes the exhaust to curl back into the cockpit, or at least the invisible (i.e. non-smelly bit) gas starts to give us headaches and nausea.
I'd love to find a cure for this but as the exhaust is low down and a long way back already, I am short of ideas!
On earlier boats the hood was up most of the time, but on our last one it was generally only up in harbour. Maybe size matters because with an aft cockpit on a 41 footer it was very dry, whereas the boat before was centre cockpit on 33ft and the spray reached nicely. Having the hood down made for much better visibility without having to get up from position A every few minutes. Mostly the only time we put the hood up was in heavy rain or on very rare occasions if daft enough to motor straight into a headwind and sea when we could have sailed it as quick or quicker, more comfortably and certainly dryer!
Mine goes down whenever I want to see where I'm going. The only time I get any spray is on the wind in a bit of a blow. Then we're all up on the weather side and all the spray goes straight down my neck. The "spray"hood wouldn't make any difference up or down. It goes up when we leave the boat to keep the rain off the ropes.
Absolutely any time. In good weather there's no excuse for having it up. In foul weather if you're at all responsible, there's no excuse for having it up because visibility is harder. When coming alongside it's a right pain. When sheeting the main you have to duck under it so you can't look up the main while you're winching (our mainsheet winch is on the coachroof)...
... EXCEPT when SWMBO insists that guests/ kids/ she wants to cuddle up forward in the cockpit out of the rain. In the interests of encouraging foul-weather family sailing (I consider myself fortunate to have got as far as I have in this respect) I usually relent in these circumstances.
Then you have debates about whether the sprayhood affords any shelter anyway. With the wind behind you, usually it doesn't: there's no spray off the bow to shield, and the wind and rain are flooding in from abaft. So sometimes on a longer passage the sprayhood has shuttled up and down depending on our tack, as SWMBO's argument wins on one and mine on another!
I now have 2. One on the main saloon & one on the aft cabin with a zipped bimini & roll up/down sides. When left, & also when overnight on mooring or anchor, the cockpit is fully enclosed - you have no idea how much more cosy the cabin is as a result.
When motoring in bad weather I can just roll up the sides to get reasonable visibility & great shelter. In better weather I can remove the bimini section & have reasonable shelter & good vis for motoring, or I can choose to have either or both down if I want. Mostly I will sail with just the main up as it allows me to use the wheelpilot & have a nice cosy slot to sit & keep an eye on things, but running in wet weather I expect that I may keep the aft one up too. It cost a small fortune but looks like it will earn its keep.
One eminent Forumite recently explained to me that he didn't have a sprayhood, as he and his ever-loving wife were both quite short, didn't really feel the benefit, had their vision obscured, and it was a £££££ option on his fine craft.
Being about 6ft, I have made a careful note never to go out with him when it's hacking down with rain or blowing a hooley
Down for sunny days, parking, when I'm on the helm and it's not too wet(can't see over, 'window' has gone opaque so can't see through); up when going downwind in case it gives us an extra nth degree of speed!
Down as much as possible when on the move, especially when manoeuvering!! Up if horribly wet with rain/spray.
Up in Marinas and on moorings as gives a bit more shelter in the cockpit with a typical chilly East Coast breeze.
As someone has already mentioned it does seem to suck exhaust smoke forward into the cockpit, so we prefer it down if at all possible when using the engine.