Hair Damage shows up later?

A healthy hair has a cuticle that is smooth and tightly packed. The cuticle is like roof tiles, the scales overlap neatly. Bleaching lifts the cuticle so the scales stick out instead of laying flat. The do go back down, but they will never be as perfect as virgin hair. When you over bleach some of the scales are destroyed. So a bleached hair has a rougher cuticle with some parts missing (AKA protein loss, or porous hair) This means the cuticle is less effective at protecting the hairs core and preventing oil and moisture from leaving the hair, so it gets dry. Dry hair is more brittle and prone to breakage. Also those roughened cuticles with the individual scales sticking out act like velcro, so every time that you wash or brush your hair it gets damaged further.
As hair is basically dead once it leaves the scalp, so it is unable to repair itself and the damage gets worse over time
Here's a link that explains the different types of damage with diagrams, you will need to scroll through as there is a ton of info lol. http://www.thenaturalhavenbloom.com/search?q=damage

Wicked Pixie explained it perfectly. Because of these things, bleached hair is just more susceptible to damage. Like your normal sulfate shampoo/washing schedule, heat styling, brushing/combing etc can wreak more havoc on hair that has been processed. Like if someone used to shampoo their hair every 3 days, heat style once or twice a week and backcomb their hair often when it was virgin and their hair remained healthy, strong and moist, they may not be able to do those same things once it's processed/bleached without seeing some damage occur from it. I think that roof analogy is great. A new roof is going to protect the home from outside elements, whereas a damaged roof won't as much and outside factors will just make it worse.

Using products with silicones can mask damage too, making the hair feel and look much healthier than it really is by creating a coating on the hairs. A lot of people are unaware of this, think their hair is healthy, bleach it and then have the surprise of breaking, elastic-y hair

Huh, would've never thought of any of that. It makes sense now! Thank you both so much for your answers, they were very informative 🙂

Sorry, nothing to add, but just had to say this is brilliant information from Wicked Pixie and KatieSiepierski... well done, gals!