Putting aside for now the question of what exactly counts as longer term volunteering in contrast to short term volunteering, here are some of the pros and cons in general terms:

Pros

• You have longer to use your skills to make some kind of impact. There is often plenty of longer term volunteering – such as sharing your professional skills – to be done at home which can better prepare you to volunteer abroad.
• You probably will also have more of a chance to get to know locals, other volunteers and ideally some of the local language and culture.

Cons

• The practical angle: for many people, it may be difficult to arrange enough time off work to go abroad to volunteer for more than a couple of weeks.
• Longer term volunteering may give culture shock a chance to set in, whereas a short term volunteer may be in and out too quickly to experience this.

The big catch: if you’re going to dedicate a significant chunk of time to one place or cause, you want it to be right for both you and the organization. While using some placement organization gives you some level of “security”, it’s extremely difficult to know in advance how it will all go.

You should most certainly research things before, but if you sign on to something before trying it out, you are doing so “blind” to some extent; if you arrive without having arranged things in advance with the intention of checking things out first-hand, there’s a chance you won’t find the “right” opportunity. Now you’ve got time on your hands and no volunteer work. Making a long-term commitment to an organization is a serious step, and if things don’t go as planned, both sides are in for some disappointment.

As with many things, there is no clear-cut “right answer”; the next best thing you can do involves researching as much as possible, being flexible and adapting, and making the most of whatever experience you end up getting involved in.