It’s very easy to find Marriott offering 35k redemptions on $150 rooms, and equally easy to find them offered on $300 rooms. Pay cash when the roomrate on a Cat5 property is $150, redeem when its $300+. That way you avoid poor redemption values.
My own records show that I’ve redeemed my 3million lifetime points at an average of 1.3UScents per point. This year, because I spent out my stash in 2016 and 2017, I’ve only redeemed 3 nights using 100,000 points at 1.2UScents per point.
Incidentally I’m also a Spire with IHG. Points on spend accumulate at roughly the same rate but IHGs promos pay out way more points than Marriotts. There I redeemed 19 nights using 450,000 points at 0.9UScents per point