Modern Buddy

Anyone use this for the duration? Talking the 15w-40 kind? Or any other. Been using the 10w-40 on my low mileage Buddy (2500) but am about to change the oil and wonder about synth? But if it ain't broke, as they say. So I figure to run the same stuff I put into my Agility 125 as I have a big 'ol jug of it

Just wondering if anyone has experience with high mileage scoots running dino for years and years and miles of smiles? I mean what to do before synth became available? I guess small engines used to last two weeks then you just tossed 'em out!

And what about the oil filter? Change at each interval (oil change) or every other? I have heard every other is ok.

i used it for the break in period, then I went to 10w-40 or 5w-40 syn. I try to get whats on sale. Castrol, rotella etc a name brand. I don't drive much either I have 3000m in 5 years. I do lots of short trips.
I use syn because I don't want to worry if all of a sudden I start driving a lot, and have to keep track of miles. I change oil and filter beginning of year.

I have an '09 Buddy 125 with 13,000 miles and I use Shell Rotella T 15W40 (about $13 a gallon.) I change oil at around 1,500 miles and do the filter every other oil change. I have pushed a few changes up to 2,000 miles. But I do like to change the oil at the start and end of the year no matter how many miles the oil has on it. I have been thinking about going synthetic but just haven't gotten around to it yet.