If the monitor gets filthy quickly you might be intersted to look inside the computer itself! Techy people say to clean out your computer once a month if you are competent to do so.
Of course, whilst often unavoidable, the best pratice is to site your computer as far away as dust, grime and pets as possible. of course this in very diffiucult to do depending on how you household operates.
I don't bother cleaning my screen(s) regularly, I just sometimes give them a vacuum once in a while. Sometimes I use screen wipes, but they tend to leave a smeery finish which isn't very helpful in direct light etc.
Interestingly i find TFT screens still collect quite a bit of dust even though they don't produce the same static field. Whether our home is just exta dusty i don't know!