Recently, Oanda has added a weekly period to their proprietary trading platform. As you can imagine this thing is not very exciting to watch on an active basis. However, I think there is predictive value available here.
For example, though it is difficult to catch a top or a bottom at this level of observation you can certainly see longer term bollinger events. Here is what looks like a bounce on the CADCHF.
A retest of recent highs near 0.9950, if that happens, will put 500 pips on the table. Is it worth waiting a month or more to earn some of that? Alternately, if you expect it is going to get back near those highs do you think there will be some excellent buying chances over the next month as price works its way there?
The longer term play might involve a smaller position. You'd have to be willing to take the chance that news events will change the course of action and possibly be willing to endure hundred pip losses for weeks.
The shorter term plays, perhaps on the 1 day, 4 hour or 1 hour might be a bit more lucrative. If you are fairly certain you know what direction the price will be moving and the charts provide a nice entry setup then you may choose to put a bigger position into play for a relatively short period of time.
Just be careful. Long term charts can move a long way in the wrong direction even if you are ultimately proven right. You'll need discipline to hold on and to let go at the appropriate times.