Over time, these rules have become more complex and are often difficult for households to understand, for practitioners to administer and for advice agencies to advise on.
Dros amser, mae'r rheolau hyn wedi mynd yn gymhleth ac, yn aml, mae'n anodd i aelwydydd eu deall, i ymarferwyr eu gweithredu ac i asiantaethau cynghori roi cyngor arnynt.