Re: CELTA or ?
The answer really depends on the requirements of the establishments for which you work, so my answer is a little vague.
If your initial course involved 100+ hours of instruction and 6+ hours of observed teaching, and if you have been working for reputable establishments that provide observation of lessons and feedback and in-service training, then a CELTA is probably a waste of money. You would do better to try to persuade the school you work for to allow you to become involved in teaching the classes you wish to teach.
If you seriously wish to progress in the profession, then it is well worth considering working towards a CELTA or Trinity DipTESOL, or, especially if you want to work in higher education one day, an MA in TEFL/Applied Linguistics.
On a personal, possibly sour note. I note that you do not wish to become a qualified teacher. Don't you think that it behoves somebody who wishes to teach to go through some form of training that leads to some recognised form of qualification?
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