How many have done missionary work? Usually, they urged the witlesses to go "where the need is greater" within their own country--often, those assignments are for a week, or several weeks. However, when you go abroad, usually it is for a year or more.
And it is usually in the dumpy countries. I remember one witless that was on several of these wasteful assignments. This couple would go to places where they were assigned--the Dominican Republic and South Africa (and that was in the early 1990s when Apartheid was just winding down). Usually, they have stories about how they placed so many rags and started so many studies--rarely, however, did they get anyone all the way to baptism.
And what a waste of time. To go on a mission, first you need to gain lawful entry into a country. While that might be easy enough if you are going to Canada, Australia, New Zealand, or parts of Europe, just try going to somewhere like Morocco, Nigeria, Egypt, China, North Korea, or Venezuela. Countries where they have a totalitarian regime and/or that are Muslim are generally much harder to gain access to--and yet, that's where the "need" is always greater. Most Christian denominations, including the witlesses, tend to target Muslim and third-world countries and always the dumpiest regions of the world.
Then, after gaining access, you need to learn their language. No big deal if you already speak the language. But, if you know English, Spanish, or French and wish to do a mission in Muslim Morocco, you need to learn Arabic. Big deal? What if you flub up? I have heard of a situation where someone intended to wish a party a future filled with joy and happiness--and because of an articulation error, wound up wishing their pants be filled with snakes and cold fish guts. While that might be acceptable if you are a guest in a foreign event and they understand that you have trouble with the language, when you are spreading a missionary word, YOU ARE EXPECTED BY THE NATIVES TO UNDERSTAND THEIR LANGUAGE AND MASTER IT! Wishing someone would have their pants filled with snakes and fish guts would blow their mission to kingdom come.
And the hardships. Usually, you leave everything behind. You might be used to electricity--only to find there is none. Water is bad--just when you thought fluoride is bad, try guinea worms and other major health hazard parasites. Malaria is as common as the common cold in parts of Africa. There are tsetse flies in places in Africa (a bite hurts like a bee sting plus you can get sleeping sickness), and numerous other biting insects that carry diseases in South America and tropical Asia. The bot fly is a problem in South America. And the weather--usually it is 40 o C most of the time and you are expected to be out in field circus anyways. Rain is no mere nuisance--in the desert regions, you can get 30 centimeters of rain in a very short time, after being dry all year, and run the risk of being swept off of a dry river bed or getting stuck in 2 meters of mud.
All that, and what do you really accomplish? Even disregarding that the whole religion is a scam, all you can do is temporarily bring your religion to a new region. The missionaries harp on how they are saving people--neglecting to say that Christianity has been spread at one time, in one form, in those regions before and has died out. The apostle Paul, arguably the greatest missionary of all time, made sure his brand of Christianity would reach north Africa, the Middle East, and southern Europe. However, all it took was one tyrant to hijack his new religion and use it to plunge Europe into the First Dark Ages. Augustine, the tyrant that did that, probably was a bigger asset to Islam than most Muslims--you pxxx off enough people with your brand of Christianity, and someone is going to want anything that isn't Christian. This allowed Islam to spread into most of the territory that Paul had done, with the remainder under the Augustine version of Pauline Christianity.
All those hardships for a religion whose platform can't even stand the test of time or that is subject to tyrants corrupting it and imposing it on the masses? And, if Paul (who was a grand master missionary) couldn't spread true Christianity and have it last in those regions, what's to say that you are going to do any better? They never say a peep about that problem when you sign up.