TackleTour

If a company offers reels in 1000, 2000, 2500, 3000, etc. what do the "half size" jumps represent? Is it simply a larger capacity spool on what is otherwise the same frame as the lower number? So, a 2000 and 2500 are the same mechanically?

For Daiwa LT reels:
1000, 2000, FC2500 share the same body; rotors and spools will be according to the size
2500 and 3000C share the same body; rotors and spools will be according to the size
3000 and 4000C share the same body; rotors and spools will be according to the size

For Shimano reels: take a look at "Size Development" table on the Japanese webpage for Stella as example (don't know th epolicy on external links, sorry). Or TP, or Vanquish. It is explained there very well.

Too answer your question- it depends on the company and even the reel model.
There are no set rules on how reels are built. Each company can size them however they please.

Thanks guys. Now I don't feel so dumb.