We're feeding our 4 month old cocker spaniel three times a day, and will cut this down to two meals a day from about 6 months.
Everything I've read suggests that you should only put food down for 20 mins and then remove what is not eaten in that time.
Our pup, unlike any other dog I've owned, is quite a speculative feeder. It can take him an hour or two (sometimes more) to finish his food, but it usually all goes.
As he's still a young dog I'd rather he ate properly, even if it takes a while. Is there any reason why I should be limiting his feeding opportunity at each meal?