> costs a lot of time and effort This is where I disagree strongly: as a programmer you should already know all ten of them [languages] and constantly be on a

> costs a lot of time and effort This is where I disagree strongly: as a programmer you should already know all ten of them [languages] and constantly be on a look out as to which of them use where. While in time my set of immediately usable for not trivial tasks languages was morphing significantly, I tried to keep my toolbox full, maintaining a solid 6 (my mind seems comfortable with that many) languages ready for work. There are some minor points I disagree with, for example, Python, Ruby, Perl and node package managers are all very good, while PEAR is/was a pain to use (a pain: I couldn't install desired package in a minute on the first try) and so on, but it's irrelevant: what I object to is a notion that it is not worth knowing or using different tools because the one you know already "offers it all".