I'll have to admit, cars' touchscreen media/navigation units are pretty convenient. But, as you can imagine, those things are very expensive to replace! For example, a new unit for a 2011 Honda CR-V is just over $5,000 for the part alone, nevermind the cost of labour. You could get a used one online for about $600—but I'd be weary of those. You won't know if the part functions properly until after installation. Of course, you could always get an aftermarket (non-Honda) unit. Regardless, it's a big hit for most of us.
Check your owner's manual for specific instructions. If the manual doesn't speak about this directly, here are some general tips to maintain your media/navigation touchscreen unit:
Avoid too much pressure when using the touchscreen. Also use your finger to tap, as opposed to your fingernail.
Regularly clean your touchscreen to avoid buildup of fingerprints and other unwanted residue.
Use microfiber cloths for cleaning.
Use distilled water. Don't spray directly onto the screen, spray first on the cloth and then gently wipe the screen.