I was in the same boat maven c1’s with a lower end kowa spotter. Sold both and bought Zeiss conquest 10x42, no regrets so far.
Bino’s on a tripod works for me most of the time. If anything might buy 15’s later.
^^^THIS! When I switched over to the ZEISS Conquest HD 10x42's it was a Game-Changer! The level of sharpness that the better glass gives you makes being able to reach out a lot more with those binos a reality.
Or things like picking out game that's stuffed into brush in the shadows much more of a reality.
Because as you can imagine, the farther away an object is.. the more pronounced your clarity or lack-of-clarity will start to show itself under those far distances.
So if you commit... and spend that bank on good higher tier level used binos. You get some serious dividends on that right away.
Whereas, when purchasing 15s or a spotter... those only give you back dividends under certain conditions that present themselves some times in the hunting situation you find yourself in, due to habitat type and terrain layout.
For western stuff that isn't just prairie, I could see high-tier 12x50's realistically making a person really happy for a good long time, as long as they can decently handhold it and the shake is within their definition of acceptable.
For Me personally, I think 10s are about my upper limit for being able to handhold acceptably without the shake of the image being bothersome to my eyes in short order. I've occasionally taken just the 15s with me... but quick manual spot checking with 15s is kinda harsh on your eyes. Because of how easily and fast the image jumps around from movement.
For hunting thick stuff, (environments similar to what people might hunt from a treestand) the FOV on 8x makes it easy to re-find the object you're curious about inspecting when you throw up the binos. But you really don't mind soo much doing the same thing with 10x's binos that are really sharp in their image though. If that makes any sense.
The time when a spotter might feel worth is like... you're hunting public land where it's hard to find anything legal... and you've got a big-bodied and tall antlered spike buck... and let's say he's like... 200yds or more... and you're trying to find out if he happens to have just enough of a nub of a 2nd point that you can " hang a ring on it". The 15x *may* help in that regard, but it might not be enough magnification to know "for sure without a doubt". But if that's not a scenario you'd ever need to fuss with, most of the time a 10x will clearly be able to show you if he's at least legal or not. Even out to stupid far distances that you couldn't even traverse in a single days time, even if you wanted to.
BUT... for certain terrain types though.... again.. OpenCountry DesertHills and stuff. 15s are just awesome for quickly and confidently sweeping thru a vast huge area and scanning and feeling confident that if something was there you'd have seen it.