Opera 10.52 Build 3353 Available for Download.

Build 3353 is the latest development snapshot of Opera 10.52 made available for download for early adopters. As it is usually the case with pre-release software, Opera 10.52 Build 3353 is intended for testing purposes only and not for deployment into production environments. Opera Software is currently hard at work on the development of the second minor update to Opera 10.50, released earlier this year. According to the Norwegian browser maker, the build is focused on delivering bug fixes for PowerPC and on KDE 4 integration.

Source -
Opera 10.52 Build 3353 Available for Download - Opera is now at over 100 million users worldwide - Softpedia

There's a small compatibility problem in this build. YouTube doesn't work and it keeps saying 'Old Flash? Go upgrade!' So I suggest sticking to the previous build and skip this one.

Is there an option to simply upgrade Opera? It's too much trouble reinstalling Opera every two months.

You can check for newer versions inside of Opera, but it only downloads final releases. If you want to download beta releases you have to visit their development blog.