So you are wanting to do a big colour over-hall, totally new look?
Here are some things you will need to consider
1. How much colour is already in your hair.
2. Your budget, total colour over-halls can be expensive!
3. These things considered, how realistic is it for my hair to look like this over one visit from the hairdresser?
While we hairdressers would love to work that miracle for you it can be A LOT more complicated than you think and can take a lot more time than one visit.
If you have layer upon layer of dark hair colour, getting to blonde might be a several visit goal.
Or if you are platinum blonde and you want to go dark, you are definitely going to need a filler (so it wont fade quickly and you will get a much more even result) so expect it to be more expensive.
You might have put your hair through the wringer going from black to blonde, to brown, to red and now you want to go back to blonde. This might not be possible, our hair can only take so much and a good hairdresser will want your hair to stay attached to your head! So is this realistic? Probably not.
My advise is take the time to talk to your hairdresser and find out what is and isn't possible, within your budget and considering what is in your hair already. We don't like disappointing anyone which is why its important to have a realistic expectation from the start.