Well I only buy stuff if I "need" in games I really like. The only things I bought, ever (I bought the 360 at launch), is story DLC for ME2 and some car packs for Forza 3. I am buying the ME3 DLC in a few days (about to finish ME2) but with the points I have I will have 480 points excess. Normally this balance will be carried forward to the future until I find something I deem worthy enough to spend on. This pretty much forces me to spend it on trivial stuff I don't really need.
On local currency, since LIVE is not available in my country, I can only get them on overseas trips. So this things is quite rare (hence why I only spend it on items I really like).