Hey everyone, I'm quite new to cycling compared to many I know. I bought a used Allez E5 about 4 years ago and have only changed the seat thus far. Did my first ride last year, Twin Lights century, and had a blast.

I've started riding a lot more now with the warmer weather, and it feels like this bike needs a clean/tune-up and some upgrades. Looking through all the upgrade options and discerning what is worth the upgrade for now is a little challenging for a newbie.

Apparently I can't post pictures in posts, cos they appear as URLs, but I think my profile has the photos I tried to upload here. The images show the parts of interest. Please let me know if there's a more convenient way for me to include these.

During my time researching, some of the more pressing concerns are:

1) Can i upgrade this cassette to a 10 or 11-speed? or should i just get another 9 speed?
2) If i do upgrade the cassette, do the derailleurs need to be replaced? front and back? what about the chainset?
3) Can I simply replace the brakes alone? maybe an ultegra?
4) Is it worth replacing these old shifters?
5) I don't even know what the BB is, or how to identify it.

I should say, my budget is around $400-500.

I'm not looking to upgrade to a top-tier bike, just parts that will make a noticeable change to the experience of cycling.
I'm currently doing around 40-80 miles a week.

Thanks for any help.

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