C++ Dynamic Memory Allocation - char* -

i'm having problem understanding part of dynamic memory allocation in c++.

i know standard practice avoid memory leak:

double* pvalue  = null; // pointer initialized null pvalue  = new double;   // request memory variable *pvalue = 29494.99;   delete pvalue;  

however, i've seen lots of source code , delete never used there free memory:

char* text = "something"; 

so question simple: should use delete every time no longer need char pointer (or other)? or there exceptions?

i've read alot , i'm getting more confused hope can me.

---

edit:

thank explanation. understand , can make changes source code without worrying!

you should delete create new, , nothing else.

char* text = "something"; 

this not create new, shouldn't delete it.

in fact, statement doesn't create anything (apart pointer) - sets text point string created when program started.