Not always. It completely depends on how long you intend to keep the phone and what your tariff requirements are. However SIM only is always more convenient in that you can change your phone whenever you want.
Well I bought my phone in 1999 and I'm still using it, average bill is a couple of quid a year - what do you think, SIM free then?

 
	 
  
 
		 
 
		 .... may take the morning off work on Friday and queue up with the noobs..
.... may take the morning off work on Friday and queue up with the noobs.. 
 
		 
		 
 
		 
 
		 
 
		
 
 
		 
 
		