Starting a company or a team
If you think that by hiring juniors you will save money and will get working application – you are wrong.
You will loose much more than money.
Yes they are low cost, but read the rest of the post to be not tricked.
Forget for nice and reliable code
Most of the time the developing is done by using some standard patterns which the experienced developers apply without even thinking. You don’t have this from a junior – you will have “private” code which in the best case will NOT work. In the worst case it will work only in one way and you will have to fix this code at the end of the project when your time is less. DO NOT give them to commit code – leave them for years working the most misarable work that you can find untill they show that they deserve to trust them.
Rewrite their code
Most of them produce code that have to been rewritten. All the code they write is code that is invented. They hope their code will work but their vision is limited because of their experience. To know where might your code will fail you have to been working for years in this field.
If a developer writes a code the chance that it will be ideologically wrong is very small. But if a junior write a code – then be prepared to rewrite big portions of your application. Things get worse when you discover this late – near the time your customer waits his applications.
Good working environment
They take the power from the experienced developers by asking them questions. And instead your powerful developers to work at full power they get distracted from work and the those with the leak souls start to believe that they are The One (by answering easy questions from the newbies). Your good developers will become like the juniors.
Prestige of the company
If you work in a company which have a name – imagine what will other think if some junior says that he learned this (code) in your company!
You are responsible for them
If something breaks – you are the one which is responsible for their actions.
I have been working with juniors for 2 years before I realize that this is not working. In case you have already juniors – make them suffer until they go away or become real pro :)