On the subject of metronomes, which is better: the old fashioned Seth Thomas wind up kind or the new electronic battery powered ones?
If given that kind of choice I almost always instinctively go for the old fashioned tried and true version. Not this time, however.
While the old Seth Thomas rigs have their charm and aesthetic appeal (and symbolic significance) I'm going to suggest using the electronic metronome.
For one thing, they have a feature that you don't find on the old wind-ups. They give you a special tone on the first beat of the measure. With the wind up metronomes it's possible (sometimes easy) to lose a single beat while playing a difficult piece at a rapid tempo. Much better to know when the beginning of each measure is. You can even set most metronomes to exotic time signatures such as 5/4 so you can practice to Paul Desmond's "Take Five." The feature can always be disabled if you want.
I remember doing scales and Hanon exercises to a metronome when I swore the metronome was either speeding up or slowing down. That became a standing joke for me as I believe that 99% of the time it was me who was speeding up and slowing down. But sometimes a wind up metronome can be at fault. I had mine checked and found that the time it took for the pendulum to swing to the right was just a little different than the time it took to swing left.
So unless you're going somewhere for a very long time where they don't have batteries, I suggest using the electronic units. Not only can they be much smaller than the wind up counterparts, but they are more durable, less susceptible to shock. And you can use them with headphones.
I even have a metronome that doubles as a guitar tuner so I don't have anything EXTRA to carry around with me.