Placing ONLY.

[Humble]

There is some controversy over placing only:
a) It should precede the word it modifies
b) It is preferable to place it before verbs, but after be and modals.
So which is better
a) Richard only works 3 days a week.
b) Richard works only 3 days a week.
Please help.
Tnx.

[Vlad_the_Inhaler]

Both are fine, but the first is more common in speech while the second is more literary/poetic.

[mykwyner]

The word only should modify the word (or phrase) following it.

"...only works..." He does nothing but work those days.

"...works only 3..." He does not work on other days.

Those sentences are not the best examples of this rule of usage. Try these:

He only sings in the band. He does not also play an instrument or dance.
He sings only in the band. He does not sing in the church choir or the shower.
Only he sings in the band. The band has no other singers.
He sings in the only band. There is just one band, and he sings in it.

[DavyBCN]

There is some controversy over placing only:
a) It should precede the word it modifies
b) It is preferable to place it before verbs, but after be and modals.
So which is better
a) Richard only works 3 days a week.
b) Richard works only 3 days a week.
Please help.
Tnx.

Both are perfect. You could put it at the end of the sentence "Richard works 3 days a week only", but this is more in everyday speech - and is often marked as incorrect in exams. Only does not always follow a modal verb, althouh again there are people who may disagree with me and say it is not "good" English.

You should only spend money if you have it - good
You only should spend money if you have it - ok but not so common.

You need only to ask and I will help - ok but not so common.
You only need to ask and I will help - good.

Try it out with other modals and see what you think.

[Humble]

Thanks to everybody.
After reading Mykwyner's post I think there might be some transatlantic differences.
I've got more examples to consider.
1. a) She can only lend you $100.
b) She can lend you only $100.
2. a) I have only come for a short stay.
b) I have come only for a short stay.
3. a) I am only annoyed when he speaks in a plummy voice.
b) I am annoyed only when he speaks in a plummy voice.
I wish MrP would have his say, too.

[Humble]

Wow, I must wet my membership!