I replaced the screen on my Kobo Clara hd recently after it broke; by far the hardest part was removing the old screen from the glue holding it on to the metal plate. Apparently newer models are much easier to repair.

Also, while you have it open (in fact, go and open it just to do this!), replace the internal SD card; they have a tendency to fail; my ereader had been getting very annoying with lag and random reboots until I did this, now runs like a dream. You'll need to copy your old sd card across or find an image somewhere (they exist on some forums) if it's too far gone (I got the bulk of my using DD rescue but there was a _lot_ of errors)

That would explain why mine is increasingly lagging as it ages. Unfortunately, the libra H2O went with eMMC for water resistance, so replacement is slightly more involved.

Thanks for the heads up. Good to know storage won't be an issue with a simple upgrade too.