Reliability and Validity for multiple linear regression analysis !

#1
Hi! Everyone!, I am ready to do a multiple linear regression study. I am wondering how many test I need to do for achieving reliability and validity before performing multiple linear regression analysis. I am reading some literature, it seems that many tests need to be done before I actually perform the multiple linear regression test. For example, in one study with Structural Equation Model (SEM) , it examined 4 tests in total need to be taken, involving two reliability tests - Cronbach's alpha and Internal reliability, and two validity tests - Convergent Validity and and Discriminant Validity. I am wondering if I also need to do four tests to make sure the reliability and validly with multiple linear regression study, ? or I can do fewer?