DIY bus tours make the most of time, writes Peter Hamling.
In these days of million-miles-an-hour travel itineraries, time can often be at a premium so the Hop-On-Hop-Off bus tour in London can be a real plus.
The concept is simple: you pay one fare for a day and can get on and off as many times as you like. In some cities, such as Paris, there are two-day ticket options for these tours, usually at a bit of a discount on the one-day price.
Seniors can sometimes get a concession. And in Singapore, show the driver a Singapore Airlines boarding pass and you'll get a special rate.
Almost everywhere, the buses are open-top double-deckers. That's a real plus for the photographers among us, and who doesn't fall into that category when on the tourist trail? Just pray it doesn't rain.
But not even downpours deter the keen tourist. We saw "top-deckers" in Paris bravely confronting the weather with raincoats and umbrellas pressed into service.
To keep track of where you are, where you've been and where you're going, maps are provided that detail the stops and places of interest. If you have the time it can be a good tactic to take the complete round trip to get the feel of the place, then take a second circuit for a closer look at things that interest you more.
On most tours you'll also be given a set of earphones so you can plug in to a recorded commentary, which is usually on offer in at least eight or 10 languages and is linked with the location of the bus.
You may find a few exceptions to this where a real person with a microphone provides the information. From personal experience, the recorded versions are often much easier to follow and more informative. It's pretty much DIY tourism - to be fully in charge, you'd only need to be driving the bus.
The truth is, these tours are as flexible as you want them to be. On a recent occasion we had two hours to kill in York before our train left for London. Right outside the station was the starting point for the local Ho-Ho, so we easily filled in the time and saw extra sights.
Inevitably there are variations on the theme. One of these is the Harrods Vintage Bus Tour of London that uses double-deckers to take tourists around such must-do's as the Tower of London, the city's financial and theatre districts, the Changing of the Guard at Buckingham Palace, the Houses of Parliament and Big Ben, a short cruise on the Thames, and concluding (as an optional extra) with a wonderful three-course lunch in the Georgian restaurant in the famous Harrods department store in Knightsbridge.
And while on the subject of buses in faraway places, don't reject the idea of using local services to get from A to B. You'll be sharing the experience with the people who live and work there, and so are likely meet some real characters and see parts of the countryside that aren't covered by tourist excursions.