Maybe I should re-phase that before I start.
You don't need official qualifications to make it in this world e.g. certificates and diplomas.
Now I'm not saying Formal Qualifications are a bad thing either and I have gathered some over the years but I have done them to further my knowledge and fuel the passion I have for that subject. Unfortunately these the main selling point seems to be that you need them to get a job so the emphasis seems to have switched from learning and having a passion for the subject to the education establishments being marked and judged on how many people pass and the teaching methods adapted to satisfy that criteria.
The result is that when looking for employment in most companies many of them won't even accept you for an online or telephone interview unless your CV qualifications sections is full of certificates.
Rare are the days when you could walk into a business and get an interview where you can get a chance to sell yourself, what you know, your experience, what life skills you have learned and what value you think can bring to this company. Most of us won't get past the "posting a CV stage" only to never get any feedback as most organisations are too rude and ignorant to even acknowledge receipt, let alone provide any feedback for you to learn from.
If can be just as difficult when setting up your own business, yes you'll give yourself the job but unless you have some proven record for the success of the service or product you are offering then it is going to be a challenge getting your business off the ground. The upside is that the ball is in your court to go out and prove your worth.
Playing or Teaching Guitar is one such area where you can take control of your own destiny. Unless you are trying of a formal role in an orchestra or teaching in a music college then playing in a band or starting a private teaching career is more informal.
If its a band you want then you can start your own band or audition for an up and running band or even create a solo act. Based on your ability, genre, market research and enthusiasm you can create a product that you can enjoy and even bring financial rewards.
Guitar Teaching sounds like a formal option but you don't need to have a degree or Grade 8 practical and theory, you don't need to know how to play every genre of music or even be able to read music. As long as you have a reasonable level of competency of your instrument, some knowledge of theory (not masses) and a belief that you can communicate effectively with your potential students then you have something incredible to offer your students.
As long as you are at least one step ahead of what they know then you are of value to them, you are more likely to be able to empathise with what they are going through as it probably wasn't that long ago that you were going through the same emotions. This valuable trait alone can help build a unique trust between you and your students. You will be better equipped to recognise when they are struggling and find ways to work around the problem and putting the student at ease.
When I was at school I was very aware of the teachers that seem to have a passion for their subject and went to great lengths to bring to lesson to life and others who were just textbook teachers that did things the same way every time and if you didn't get it then Tough! Go to the back of the Class and where the Dunces Hat.
I think it's a lot better these days but that attitude had a profound effect on my willingness to learn, how can you effectively learn what someone doesn't seem to want to teach, the lack of enthusiasm given off by the teacher just ends up rubbing off on you.
As a private teacher running your own business you will have a passion for your subject and this will be picked up by your student's.
Now I know don't everyone will agree with the views I have expressed here and that's fine, it's about freedom of choice and doing what you believe in but for me I know what works for me. I left school with few qualifications but when put in an environment of my choosing my hunger for knowledge grew exponentially. I was no longer shackled to a blinkered education system and started to enjoy life, learning and making my own choices. Despite my lack of certificates and diplomas I have managed to work all my life choosing what I want to do and when whilst enjoying every moment and that to me is everything. Rock On!