Hang onto those old managers.In advance of this weekend's 'Managing for Success' conference, Michael Simmons argues that law firms must invest in experienced people.We tend to make the best and brightest lawyers our managing partners.

Once a firm gets above a certain size, management is considered to be a full-time job.

Adequate management training is available, and the enlightened law firm should ensure that the managing partner designate is given at least the rudiments of management training.

At the same time, he or she will be emptying the desk of client work.Is this sensible? Bear in mind that the shelf life of the average managing partner is decreasing.

Most law firm managers today are elected for three years with a provision for a further three years' extension.

Many fail to take the extension up; many do not last the first three years.

Lawyers are an unforgiving species.

Mistakes are held against managers; confidence is soon lost on both sides.Most managing partners experience an initial honeymoon period during which they can do no wrong.

The new broom syndrome is involved - at least you are not the same person as your allegedly discredited predecessor.

The honeymoon period is followed by six months when, conversely, you can do no right.

This is a time when suicide seems a decent option.After the extreme swings of the pendulum, the chances are that you settle down into a relatively humdrum existence.

If you make correct decisions, that is what you are expected to do.

If you get it wrong, as you will, then do not expect to be forgiven.Is it surprising that a 'them-and-us' divide speedily appears between managing partners and those that they are managing?Incomprehension and ingratitude in relation to the management role causes increasing isolation in the managing partner.

It is a lonely job.

It is difficult to talk to any of your partners about your problems, unless they themselves have been through the experience.Having divested yourself of clients some years ago, now that your management role is to be terminated by the effluxion of time or worse, what do you do next? Legal skills need to be constantly kept sharp.

Yours, through lack of use, are blunt and also rusty.Do you have the courage to go back to what you did before? The problem is that there is almost bound to be a hiatus before you become an effective fee-earner again.

Are your partners sufficiently enlightened to allow you a honeymoon period?On the basis that you lack the confidence, and they lack the patience, what can be done? There does not seem to be a market for a lawyer manager to take up a similar role in another firm.

It may develop some day, but for the moment that particular road is blocked.Several in this position have sought to use their skills as law firm consultants.

The demand is of necessity finite, but this can be a useful translation.

Others take the view that they have had enough of the law and lawyers, and go into business, sometimes with their former clients.

Either way, they are lost to their law firms.I have already referred to managers being chosen from among the best and brightest of lawyers.

In their time in management, whether perceived as successful or not, they have acquired invaluable commercial skills.

Far too many commercial lawyers are despised by their clients as necessary evils, who produce pretty documents, but otherwise have no conception of the commerciality of the transaction.

The ex-managing partner has had the opportunity of learning the ebb and flow of business.

Combine these with good commercial law skills, and you have a valuable professional who in turn should earn valuable fees.By failing to embrace those who have acquired those useful new talents back into law firms, solicitors are committing an act of folly and waste.

People are assets.

Those who have acquired business skills are the most valuable.

Let them go elsewhere at your peril.Michael Simmons is a partner at Finers Stephens Innocent in London and a consultant on professional practice problems