I think tools should be kept safe indoors because:
-It would be easier for you to find them.
-It would much safer, otherwise someone might accidentally step on it or trip on one of the tools.
-Some tools may get rusted if left outdoors due to the humidity and it might not be safe to use somehow.
I think ladders should be kept indoors because it could be very dangerous, it may fall at anytime and may hurt someone.You also wouldn't want any animal to set their nest there, would you? So it is better to keep ladders indoors and to lean them onto something.
I hope this helps :)