Seriously, with 285,000 miles on it, you've done well. Why change oils at this point? A 0w30 would give you better start up, but the use of other viscosities clearly hasn't made a big difference in engine life.
My truck leaks about a quart every 1,500 - 2,000 miles. Mostly from the oil cooler, some from the rear main seal. I should fix it...one of theses days...but I've got a lot of other priorities ahead of that rear main seal job. So, I buy oil on clearance. The QS in it currently was .98/QT. the Castrol Edge that had been in it was $1.98 / QT.
So, if you start using oil (actually using it), then you can either a) fix the problem, which is expensive, or b) buy cheaper oil...