All praise is due only to Allaah. We laud Him and beseech His

Fourth harm
As many sons and daughters-in-law populate your home, 
proportionately the worry and problems will increase for you. 
With each new addition there are more problems; sickness, 
arguments, birth of children, etc., etc. The more this burden is 
lightened off you, by your sons living separately, the more 
peaceful your life will become. 
Our humble suggestion is that if you are self-employed and 
have the means, then it is best to let each son establish a 
separate business. The further away each one works and lives 
from the other, the greater the bond and affection will be. We 
may think that there is goodness in all being together, but the 
associated problems, is something which experience teaches. 
So many incidents arise regarding the problems experienced by 
families that live and conduct business together. Hatred, 
jealousy and greed are inherent in all such situations. 
What is meant by separate quarters for your son and a 
suggestion
If one is not of the means to provide separate quarters, then a 
small room, flat or even a separate section of the house to 
which they have the keys so that they are allowed privacy. 
Providing a separate kitchen in essential, even though it may 
not be a modern one. 
162
In most cases, if the money spent (wasted) on large wedding 
receptions and Walimahs is saved and kept aside, then this will, 
in most cases, be sufficient to pay the rent for many months. Or 
this money can also be used to build separate quarters for your 
son and his wife on your property. 
When a person gets married in order to save himself from 
immorality and sin, then Allaah Ta`ala will make means for an 
easy sustenance for him. Allaah Ta`ala says in the Qur`aan 
Majeed, 
“If they are poor, Allaah will enrich them from His 
Bounty.”
[Para 18] 
In essence, a person should not hesitate in getting married 
purely on account of not being wealthy enough. When a person 
has trust in Allaah Ta'ala, the He become sufficient. A couple 
can live nicely and amicably on even the bare necessities, 
provided they are content.