You should increase your CPC only gradually, ideally by a maximum of 20 – 30 % at a time. Once you’ve set a new bid, leave it for 2 – 3 weeks, periodically review your campaign performance impact, and if you’re happy with the results, continue raising your CPC bid. A more specific setting has more weight – if you increase the price per category and then set a different price for an individual product, the price set for that individual product is always used.
With price bids for categories, you can also see recommended bids that should drive traffic and are an indication that you haven’t set your bid too high. However, it is advised that you achieve the recommended prices only by gradual increase, especially if the value is many times higher than the currently set or minimum price.