As someone who hasn't had their natural hair color for longer than a few weeks since they turned 13, I know a thing or two about dying my hair. When I lived at home, my mom would take me to the salon to have our hair dyed together. However, when I turned 18 and moved to college, I had to pay for my own hair care. I'm in college, I'm a bit broke-ish. So here is what I do to save the moolah and look amazing.
1. Use a color-friendly shampoo/conditioner
Regardless of if you dye your hair yourself, or always go to a stylist, using color-friendly shampoo will keep your color longer and will save you $$$ in the long term. You can get very expensive salon quality or there are drug-store brands that do the job.
2. Hair clips are your friend
This one should be a no-brainer. Clip sections of your hair up and work from one section to another. This will help ensure you get every strand.
3. Don't wash your hair more than you need to
This is just a general hair tip; but applies to dyed hair. Washing your hair more than necessary dries out your hair and scalp, but it also washes away dye. This along with swimming in chlorine treated pools and exposing your head to the elements with effectively fade your hair. Dry shampoo/condition can help with sweat/oil buildup if you can't/don't want to wash your hair.
4. Color depositing shampoo/conditioner
This stuff is the bomb.com. Instead of having the shade fluctuating, color depositing products keep your hair basically the same color until you choose to stop using it. Products like Overtone allow you to mix and match your shade (especially if you have unnatural colors), and they have products that match your need.
5. Go to stylist at least twice a year
Whenever I make it home for holidays and breaks, I make a point to see my stylist at home. I trust him and his opinion on my hair. He keeps the best interest of my hair in mind, while respecting my wishes with what to do with it.
6. Put Vaseline or heavy lotion around your face/ears/neck to prevent dying skin
If you're doing this all yourself, you might accidentally dye your ear. When you do this, you're putting a think layer between the dye and skin you don't want to be teal. If by chance you do though, this stuff is amazing for helping to un-dye your face and ears.
7. Always, always, always moisturize hair
This is another main hair tip, but will defiantly help with dyed hair. Coconut oil is the best product that I have ever used to seal in moisture. There are also specialized products that can help, but good old fashioned coconut oil has been the best for me.
8. Speak to a stylist before bleaching
Bleaching your hair can damage your hair beyond repair. It's honestly so risky if you don't know what you're doing. I recommend that if you want to, speak to a stylist about it before you do it.
9. Be aware of your body before drastically changing your color
I had a stylist that always said, "Brunettes should be brunette, and blondes should be blonde. Your face was built for your hair color." That always stuck with me, especially after I was blonde for a brief period *shudder*. Your body/skin tone/eye color were meant to look the best with your given hair color. If you want to change it, consider how it would look.
10. Actually just don't care if your roots are different from your ends
It's college, no one expects you to look 100% all of the time. Most of the people you see every day probably couldn't afford to re-dye their hair every month. I doubt they'll criticize you for buying food and not hair dye.
While the best option is always to go to someone who knows best and has been trained, that doesn't necessarily mean you're bank account will be happy with you. If you have any doubt, always talk to a trained professional. If you do mess up though, hair grows back. Happy dying!