The decision to hire a lawyer is at the core of the issue an individual choice that should be undertaken with an eye towards the costs and the benefits.
A disclaimer- recall that as an attorney who handles these cases, I have a vested financial interest in people hiring me. I don't think this changes or impacts my opinion, but it is fair for people to understand that the outcome does matter to me.
For those in the IDES (or those few legacy cases that remain in DES), there is always the option of using military attorneys at no cost. Starting with that issue, here is my take. Just like with paid civilian counsel, there are different quality of military attorneys. There are some very qualified and I think good military attorneys who I think do a great job. Depending on the individual attorney and which branch, though, you may find attorneys with very little experience or skill with these types of cases. Another issue with military attorneys is that, generally, they have no experience with appeals past the PEB level and, therefore, they may not be a good choice if there is likely to be an appeal.
Turning to civilian attorney and what they can do (and their value early in the process), here are my thoughts. In some cases, there is essentially no need for an attorney at all. That is, the case is prepared and evaluated correctly by the MEB, the issues are clear and undisputed, and the member is going to and does get a great outcome that they are satisfied with. In those types of cases, I would think there is no need to secure civilian counsel and the money for services is not well spent. However, if there are issues with the case and the outcome is not good, then having a qualified attorney, even with the costs involved, is absolutely needed to maximize the chances of a good ultimate outcome. A problem, though, is that if you forgo the attorneys help until late in the process, you may have missed early opportunities to present a good case and changing the outcome may be harder or impossible. A further problem is that often members going through IDES/DES do not know what issues are in their case or do not get an indication of a bad outcome until they get the results of the IPEB or sometimes the FPEB. Essentially, I think in some ways, having representation early may be somewhat like "insurance"- that is it may not be needed, but if something is going wrong, you will have wanted to have early representation. Again, this is all part of the "cost/benefit" analysis.
As for what an attorney can do before the MEB, it depends on the case. But, sometimes there is a lot to be done. Here are a few examples. (This has happened several times over the years, and have had variations of this with cardiac conditions where METS tests were not accomplished instead of PFT tests, with similar outcomes) I had a case where a member was treated and was evaluated for an "asthma-like" condition. She was never evaluated with a proper Pulmonary Fitness Test (there was no administration of inhaled medicine to get a valid predicted percentage of function), but her condition indicated quite serious limitations. Based on medication prescribed, it appeared that the member was set up for a 30% rating. As the case was being evaluated, I advised the member to get a referral to a pulmonary clinic and to get a properly conducted PFT. The result showed a disability equating to 60%. When the case finally moved through the MEB and the PEB, a 60% award was made. (A fair question is whether it was early representation that mattered- i.e., this may have been able to have been addressed later in the process...but, on the other hand, earlier valid examinations may have influenced both the MEB and the PEB in coming to an early correct outcome). This type of situation occurs fairly often.
A much more common occurrence is early counseling on what the members goals should be and strategies for reaching that goal. In maybe 10-20% of cases that I get involved with later in the process (post- IPEB through appeals), the member initially wants a different finding than they finally contend for. Sometimes they argue they are fit initially, gather all kinds of evidence showing how they are able to perform their duties and in some cases, make statements to their doctors that become part of the MEB or submit letters to the MEB before it is completed, but by the time they get to the FPEB, they change their minds and are fighting for retirement. In other cases, they do the opposite and are preparing early to show that they are unfit, but at the FPEB, they decide to argue that they are fit. In both cases, the earlier statements and evidence can present significant problems in reaching their desired outcome- and in some of these types of cases, you risk ending up with a less desirable outcome- severance at 10 or 20% rather than either a fit finding or retirement. (Note that early advice and representation could have obviated all appeals- a case prepared properly early could have meant a smooth MEB and IPEB with consistent findings and evidence the whole way through resulting in the member getting what they ultimately wanted; but, in some cases, the same outcome would occur no matter when representation was secured). Again, in some cases, earlier representation would not be necessary, and later representation served just as well as earlier. But, my experience says, earlier is better in these situations as it maximizes the chances for the PEB to come to a good outcome earlier rather than having to go through appeals to try to get the desired outcome. Much harder to backtrack and fight earlier positions than to have a consistent approach throughout the case.
A fair point, though, is that in some cases, there really is nothing to be done until the MEB results come back. This all goes back to the fact that each case is different and the need or desirability for an attorney at different points in the process is an individual choice.