"quoting" column names

Hi

I've been using Postgres for... well, as long as I can remember ;)
And aparently I've been using a column name wich is "almost reserved"
(i.e. cannot be used as identifer). Since upgrading to 6.5 I nolonger
can access these fields the way I've always done them. This what I've
been doing:

create table login (userid text, when datetime);
select when from login where userid = 'xxxx';

In 6.5 I have to do:

select "when" from login where userid = 'xxxx';

My question now is, should I always quote column names, just in case,
or should I only quote column names that are "almost reserved"?

/Kudo
-- 
ech`echo xiun|tr nu oc|sed 'sx\([sx]\)\([xoi]\)xo un\2\1 is xg'`ol
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