A lot of people probably make the assumption that adjustable spanners are better every time, but this isn’t always the case. They each have their pros and cons, and seasoned tool-users usually end up with opinions of their own of when each should be used.
Adjustable Spanner Merits
Adjustable spanners can be great tools, particularly for people who aren’t really used to using spanners in general. As they can be quickly adjusted to just about any size, it means that you only need one tool, which can save money and time by eliminating the need to constantly switch out the tool for more suitably sized spanners.
Thanks to their adjustable size, a layman can quickly learn to use them, by eliminating the need to actually learn about what size is suited to what task.
Also, when the sizes of nuts and bolts aren’t standardised, an adjustable spanner can come in handy.
The main benefit to an adjustable spanner is the incredible convenience of just having to use one tool for the entire process; there is no need to switch out tools or carry around a massive group of them whenever you’ve got a job to do.
Non-Adjustable Spanner Merits
The biggest limitation to the adjustable models is that they need to be at the same scale as a large spanner in order for it to perform the larger tasks they’re used for. This may not seem like such a big deal, but I’ve often encountered situations where the only thing I can fit into the space available is a smaller spanner.
Many tool-users would agree that the right tool for the right task has a great feeling. With a non-adjustable wrench which is the correct size, it feels solid and well suited for the task, whereas an adjustable spanner just doesn’t quite feel as natural.
Once you know what sized spanner is required for what nut or bolt, it can be very quick and easy to switch out the one you’re using for the correctly sized one.