In our housing community we HAVE to have mini blind on all the windows, and they CAN'T be broken. If they are broken they want you to replace them immediately. Well guess what... I have 3 YOUNG kids. They like to look out their windows, and they can't pull the strings to open the blinds so what do they do? They BEND them. You can only bend mini blinds so much before they break, thus resulting in an almost constant need to replace mini blinds in the house.
So instead of buying a new set of blinds every 2 weeks, I kept one set of old broken ones and I just replace the slats when needed. Here, let me show you how.
There are little plastic buttons on the bottom of the blinds
Use a flat head screw driver, or butter knife to pop out the one on either end. You can leave the one in the middle.
Now pull out the string that runs through the middle, and untie the knot. If you can't untie the knot cut it as close as you can to the knot and burn the end so it doesn't unravel.
Pull the string up through the blinds till you get to the top of the broken ones.
Now pull the broken slats out the side
Now just slide the new ones in, feed the string back through each slat down to the plastic bar on the bottom. Tie a slip knot so the NEXT time you have to do this it will save you some time, and shove all the string back in the hole and snap the button back in.
NOTE: mini blinds are not universal, make sure you get the same kind so the hols line up. Another option is to take the extra slats off the bottom of the blinds, since they usually extend several inches below the window.