how accurate are the RS guides on entry fees

You might give some examples that you are looking for, but most fees are available online if you look.

We always found them to be close if not accurate. Remember by the time a guidebook hits the street it is at least six months out of date and fees can always to be increased some.

If you have the current guide it is usually right on. But don't forget, he usually publishes in November for the following year, so if you are going in July or August, there is a really good chance that prices have risen some. We found in Scotland, some of the major destinations (Edinburgh Castle in particular) had gone up - but not so much that it messed with our overall budget. Like Frank suggested, check online at the sites themselves. They are likely to be more accurate than his book. I use the guides to do just that - guide. For specifics I always look online or email (in the case of accommodations).

They're usually within 2 euros I've found, and sometimes even the websites are a bit off!

Thanks everyone- good to know the budget is on track-

We joke about the 1.50€ that he seemed to be constantly off on a recent trip. With one exception - the 2010 guidebook I had was 7€ off on one place. I nearly choked when we got to the ticket window. To make up for it, we got one audio guide for our family of 5 and I spoke the information to the rest of the family as we went through. It's best to check the internet before leaving if you're on a tight budget. Especially if you're with kids. Some places are free for under 6, some for under 18 and recently we've found a few places (Italy and Greece) that are free for EU children only.