It is a time of joy and angst for midsize law firms and their lawyers. For the first time, they are experiencing big demand from big business. Under pressure to cut legal spending, a good portion of corporate America is dumping high-priced big-city law firms and substituting smaller, lower-cost regional firms. Phones are ringing at midsize firms with invitations to make pitches and respond to requests for proposals.

However, there is plenty of anxiety to go around at law firms of all sizes. The rules underpinning the business side of law firm life are nearly unrecognizable from just a few years ago. The economic crisis that began in spring 2008 amplified the impact of those changes — which have been under way for years, according to law firm consultants. Firms faring well despite the recession are doing things differently, advisers said in a recent series of interviews.