While it may be true that small law firms are more susceptible to breaking up, I have seen large firms break apart as well. I have been working for a small law firm for over three years as a paralegal (I am a 1L, evening division) and our business is pretty fluid and secure. Since I have been in this business, I have only heard of a couple small firms going under, and that is because they based their entire firm on one large insurance client, or something similar. I don't think the size of the firm really matters, its the management/ownership and type of law that can sink/swim a business.