Small engine life expectancy

Short post.Z125 maintained by the book and ridden hard. Just high RPM cruising because I need to keep up with traffic on a 50mph road for my commute. 25,000 miles currently. Keeping the bike as only vehicle until it dies because it’s so cheap to maintain and gas up. Should I plan to save for another bike such as a 650 when I get close to 30k or will I start to hear, smell or feel when the engine gives and have some time to save up?And if something goes is it worth repairing or do most engine problems on a bike = new bike time via /r/motorcycles https://www.reddit.com/r/motorcycles/comments/ebci89/small_engine_life_expectancy/?utm_source=ifttt