could formatting my mpb 10+ cause issues?

[Trance]

will it ruin the hd?

when my computer gets cluttered i want that 'fresh' feel again and format

 

[GGJstudios]

will it ruin the hd?

when my computer gets cluttered i want that 'fresh' feel again and format

No, formatting cannot ruin a drive.

 

[Ccrew]

And frankly, a Mac isn't like a Windows machine, while it can get some clutter it doesn't need all the "optimization" or even reformatting that a Windows machine occasionally does.

OSX is essentially BSD with a pretty face, so many Unix rules apply.