Ever wonder how this whole color thing works? Let me lay it on you. Here is as much info as I can give you on what to expect when going lighter.
Everyone's hair has underlying warm pigments. If you are dark haired.. you've got more red-orange pigments. If you are lighter.. you've got more gold-yellow undertones. To remove those pigments we use lightener. It has to go through the stages of red-orange-yellow, then we hope to get it to that perfect pale blonde. Like the inside of a banana. The lighter you are naturally the easier and faster you'll get to this destination.
Naturally Darker Tones
So what if you are darker naturally? It's going to take multiple sessions of lightening. (But what about Kim K you ask? Kim spent at least a full day in the salon, sacrificed quite and a bit of length. And I can only imagine the $$$ she spent for that platinum.) Expect to book out multiple appointments. The first couple of times you may be more of a golden natural blonde color. Each time it will get a little lighter. You also have to remember that some hair textures/colors just won't get that light. Talk to your stylist and ask for their honest opinion if they think this is a healthy option for your hair. It's worth it to spend all the time and money getting light if the end result isn't going to be healthy and beautiful. Enhance your hair and do what's best for it.
Side note, you also must keep in mind that when you see a celeb do a major hair change a lot of the time they do lose a good amount of length.. the majority of these girls are wearing extensions that make it appear long, blonde and healthy.
Salon/Box Colored Hair
If you have been coloring your hair darker in a salon you'll have an easier time getting those pigments removed but this isn't to say it'll be a breeze. It'll still take a few appointments to keep the intregrity of your hair strong. If you have been box coloring your hair this is a whole different ball game. You will need to be open to the idea of going through multiple stages, possibly red tones at first. Box color just does funny things and there's really no telling how much lighter you will get it in one try without doing a test strand first. If you have box color on your hair I would highly recommend scheduling a consultation prior to your appointment so that your stylist can book out the appropriate amount of time for your hair.
It's important to think about how you will be taking care of your hair after your color service. It's good to get in the habit of prebooking your appointments, usually every 4-8 weeks. Ask your stylist how soon you should be coming back. It's also important to invest in good product to upkeep your color and keep your hair strong. It's best to use a sulfate free shampoo and conditioner. This will keep your hair from drying out and keep your color from fading/turning brassy. If you are going for the cool ashy blonde tones, invest in a purple shampoo to upkeep your color at home. It also important to be using leave in conditioners for added moisture, and a weekly deep conditioner.
Besides going blonde, its a good idea to do the research before making any major hair change! I hope this helps any of you who are considering a lighter shade. I'm happy to answer any other questions I may have missed!