Excellent all 'round .
I began using fully synthetic oils long ago, I also don't use 40W etc. because you want the oil to get up out of the sump A.S.A.P. upon initial startup .
I can't imagine waiting 5,000 miles to do a
HOT L.O.F. .
I remember some chrome aftermarket Harley-Davidson oil filters giving up the ghost and destroying engines but never a Toyota .
The sludge thing confuses me as I see it as
bad engineering .
I'm sure many sludge up because they never run the engine long enough to fully warm it up, back when paraffin based oils were the norm I ofen encountered badly gunked up engines, I used synthetic oils to clean them as I drove them -BUT- one must be *very* careful and diligent to not drive one over 100 mile as the sludge often comes loose and can (not will) plug up the oil intake screen in the sump .
This happened to me a while back when I trusted someone else, the poor old '59 got starved for oil and blew a connecting rod right through the case
.