What exactly does 拆开 mean and is it commonly used? I've been trying to figure out how exactly to use 拆开 and what it means since I saw it in a song: Mine, Mine by 周杰伦.

In the song, the translation i got was disassembling which i would think to be like taking something apart? Though i also get the definition online as to take apart  or separating, with examples of opening letters and presents: 

你不等我就把所有的礼物都拆开了？
Would you commonly use this for opening gifts/letters or also in other contexts to mean disassembling something?
Thanks!
It's fine to use "拆開" to open up a gift, or a package, box, etc., "打開" is also applicable.
For disassembling usage, you might to take apart something 3C products or electronic/mechanical devices, like cell phone, radio, television controller, etc. Use "拆解" also applicable.