It depends on the city and your specific plans and days. Spending some time with a good guidebook will help as most give pretty good descriptions of the available options. I think guidebooks generally overestimate the value of these passes. For example, one of the better deals in Paris is a week-long pass, but it’s for a Monday through Sunday week. If you’re going to be in Paris for Thursday to Tuesday, or you’re taking an overnight trip to Normandy in the middle of your stay in Paris, that specific pass wouldn’t be a good deal. Also, in many cities you won’t necessarily use a lot of public transportation. In Rome we stayed near Termini. We took the subway out the the farthest place we intended to visit each day and then worked our way back toward our hotel on foot, with the idea that we’d catch subway or bus if we got tired. We only took the subway back one-day because it was raining, so the all day transit passes were a waste of money for us in Rome. While the guidebook raved about the great deal you get with the Helsinki card, I can’t see how you’d ever make it pay. We took a round trip ferry and visited three museums that were covered during our 24 hours and didn’t cover the cost of the pass.

The passes do have a convenience value, especially if you’re not traveling solo. I doubt the daily passes saved us money in London, but I considered them a good buy. Passes are good on both the tube and buses. It was very handy not to have to buy tickets for each tube ride and not to have to deal with correct change, etc. when hopping on the bus.

Was that the Oyster Card that you used in London? We’re trying to decide if it is worthwhile to purchase them.

Some cities sell a strip of tickets, say 10 tickets for the cost of 7. I like this because it gives you more flexibility than a pass, which is usually limited to an unconvenient time period.

However, most tourist areas are very compact, and walking is the best way to get around. I’ve left more than a few unused tickets behind because of this.

An exception might be Venice, where a vaporetto pass is a good deal, since you need to use a boat to get to some of the interesting areas, and a circle ride on the grand canal at dusk is a great experience on a vaporetto, just as good as a gondola, and a fraction of the cost.

I’m leaning towards getting Oyster Cards and child Travelcards when we’re in London because there will be five of us, and as oldlady said, it just seems much more convenient.