if never used it will just show no transactions linked to that address.. when checking block explorers.
to 'save' all possible addresses would require storage beyond any measure/availability today

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there are 904625697166532776746648320380374280100293470930272690489102837043110636675 possible private keys

use this http://gobittest.appspot.com/Address
type in 1 at: '0 - Private ECDSA Key' text box
it will give you: 1EHNa6Q4Jz2uvNExL497mE43ikXhwF6kZm  at: '9 - Base58 encoding of 8' text box

type in 2 at: '0 - Private ECDSA Key' text box
it will give you: 1LagHJk2FyCV2VzrNHVqg3gYG4TSYwDV4m  at: '9 - Base58 encoding of 8' text box

continue for as long as you like until your fingers burn out from keyboard friction.. or even make a script to automate it.
the number is so huge it wont matter.

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you can build a new script that not only makes the keypairs for your computer to store
requiring storage way way way beyond even a yottabyte hard drive


then if checking the balance. which by the way requires much more computational power and bandwidth.

seeing as how there are 904625697166532776746648320380374280100293470930272690489102837043110636675 possibilities
and imagining you could check lets say 1000 addresses a second.

1000                     =1 sec   
60000                     =1 min   
3600000                  =1 hour   
86400000                 =1 day   
31536000000            =1 year   
788400000000           =1 family generation   
78840000000000        =100 family generation(ancestors)   

after 2500 years your ancestors would have only checked
78840000000000   possibles

in other words after 2500 years your ancestors would have
904625697166532776746648320380374280100293470930272690489102758203110636675 still to go
of
904625697166532776746648320380374280100293470930272690489102837043110636675