Ok, basic knowledge tips from a tattoo artist:
Salary: I will not disclose the amount I make, mainly because it varies. There are weeks where you make an extremely large amount of money (You work your *rse off, but the results are lucrative) and there are weeks where you make next to nothing. Being a tattoo artist is incredibly hard work, as you have to really manage your income in order to support yourself. If you made £5000 in one week and blew it all, then the following month you made nothing, you would have serious issues. Therefore, money-management is paramount!!
Apprenticeships: Here in the UK Apprenticeships last as long as they need to really (I'm pretty sure it's similar everywhere else, but don't quote me). My apprenticeship was only around 3 months to learn basic safety and hygiene management, then a further 9 months for equipment handling and practising on synthetics / pig-skins and a final 3 months of client management training....DONE. I got my license around a year after I first began my apprenticeship, But, again, everyone varies. I had been drawing and doing advanced art for around 14 years before ever going into the industry and had already received a wide knowledge of tattooing via my Uncle (Tattoo Artist) and my other artist who did my tattoos. It depends on the knowledge you already have of this industry, your drawing / artwork skill levels and your drive / time-management. If you really want to succeed in this industry, you need to be prepared to put your all into your apprenticeship. There were times where I was in the studio 7 days a week, until 11pm at night cleaning, ordering supplies and booking clients....It's a $hitload of work and it never stops. Even now, I need to do the small and mediocre tasks because otherwise, my studio will not operate professionally or correctly. You need to ask different studios in your area regarding timings and days that you'll need to be there, but take it from me, the more you go and the longer you spend, the more you will learn (^_^)
Parlour: I will not answer this, as you will need to be a licensed tattoo artist before opening up a studio. It's incredibly difficult and time consuming. You need to have all kinds of resources at your fingertips. Connections with suppliers, health and safety department regulations, full license, experienced artists who you know and trust and often, you'll need investment, as it's extremely expensive to run your own studio and at first, all money goes out and you see no return on it for at least the first 6 months!!
Piercing: You can be a piercer and a tattoo artist, but you need to qualify in both. Usually you can acquire piercing knowledge during your tattoo apprenticeship, but with the tattoo apprenticeship being elongated and such hard work, often you might be taking on too much at one point. Again you will need to become a licensed piercer, as well as a licensed tattoo artist. (You can get joint licenses, but these are rare and highly expensive) One task at a time ok sweets :)
Our suppliers only supply to professional, licensed tattoo studios. Most reputable suppliers will only do this, as it's a way of ensuring that there are less Scratchers in this world and more professionals!!
The only way to establish yourself in such a widely acknowledged industry is to get your portfolio really maximised, do as many celebrity plugs as possible and attend conventions regularly. Tattoo there if possible as well. Again, you need to be a talented artist to do this (In my book) but there are those who got to where they are based on their personal contacts in the industry and the celebrity world. Personally, I prefer to concentrate on establishing myself based on my skill and my custom work that I pride myself on. No one can replicate my tattoos because they are 100% mine and the details, line work, imagery, angles, contours and shading are creations of my own hands and personality.
Opening Hours: Again not sure about the States, but yes. Many studios are closed on Sundays. We are NOT closed on Sundays and many of the studios here in London will be closed to the public, but will open for specific clients who are investing their time in the studio and the artists there. Another reason for closure is most likely licensing requirements. Some parlours do not have the permits to open 7 days a week or on a Sunday. The main reason I imagine is that we are only human and need a bloody rest once in a while lol!!
I hope the above information has been of use to you and if you are pursuing an apprenticeship, I wish you the best of luck. Don't forget, the ONLY way you will learn the real tricks of the trade safely and honourably, is to gain them through apprenticing under an experienced professional tattoo artist like all of us had to. Get your portfolio sorted out, knock on doors, ask as many questions as possible and keep fighting until you get it.
Good luck :)