It's so much more than 'just a name'. It's who I am. My identity. My heritage.
I changed mine, and for my specific circumstances I would again. I had a weird situation:
-Sibling A: Birth certificate in the names of 'Jones' - long story but not father or mother's names, but went exceedingly well with first name!
-Mother married, become 'PantsName'. Sibling A becomes also known as 'Pantsname'
-Sibling B born - surname 'Pantsname'
-Mother and Mr Pantsname divorce
-Mother then has me with Mr Smith. Birth certificate has surname 'Smith'
-Mother and Mr Smith break up when I'm young. Mother starts having me also called 'Pantsname' and succeeds in getting this on all official paperwork including passport, but never officially changes it so birth cert says 'Smith'
By the time I got married:
-Dad (Mr Smith) was nowhere to be seen and hadn't been since I was 5
-Sibling A (the only one I'm close to) had changed name back to Jones,
-Sibling B is an abusive dick
-Mother isn't even attending wedding.
Funnily enough with a messy history like that, 'Pantsname' never felt like much of a part of me, my identify or my heritage. It was also a bloody ugly name. The mismatch between birth cert and other docs was, at times, a pita so I was going to have to try and formalize it anyway so I decided to just go with DH's much nice surname. I felt more of a bond with his name which I'd actively chosen than with either of my options.