I've been using 10w40 conventional ever since I bought my first car in 1977 and still use it in all my cars. You know the old saying "if it ain't broke don't fix it". All the oil I'm currently using in my cars is new/old stock that I bought 15-25 years ago when oil could be bought for under a $1 a quart. I've got some newer oils that I've bought in the past few years when there have been good sales on it but being 60 years old, being disabled and not driving near as much as I used to I'm not likely to live long enough to use much if any of it since I still have several cases of the older stuff. I've got a dozen 5qt. jugs of 10w30 Pennzoil Platinum that I bought probably 15 years ago when they had it on sale and also had a rebate on it. Final cost on the PP was $1/qt. plus tax. I do my own oil changes and am still doing oil changes for under $5. each because, I also bought lots of oil filters at stores that were closing them out for $ .25-$1. each. When I bought the Versa I ordered a dozen filters from Rock Auto with a final cost including shipping of $2. each.