For starters, the typical infant's layette list includes bedsheets but it doesn't really explain or give an idea of how much one would really need.
In our case, the waterproof pads were a life saver. Prior to using them, we've always had to keep changing the sheets on the bed (crib or on our bed, since we started co-sleeping) because our little one keeps on soiling them. Pee, poo, wet burp, drool, ... name it, and he's done it. The pads were a better option compared to the sheets because we have to take everything out of the bed (pillows, blankets, etc) and put it back to change the sheets but replacing the pad just takes 2 seconds.
I'm writing about this now because my son has been throwing up a lot again the past few nights - he is congested (yet again) and has a hard time spitting up his phlegm. When he coughs and tries to expel his phlegm, other stuff come out. *sigh* On some nights, his cough gets so bad that we've had to replace the pad 3 times (we have a total of 4).
Hope this congestion goes away na.