You are like most investors, the 401k/403b being the second largest asset typically after a home. The problem is that people have their own careers/jobs/family etc... to worry about and most do the traditional pie chart of funds and then 'ride it out' hoping for the best as they tend to forget to pay attention to the account. (out of site out of mind)
In a bear market buy and hold does not work. If we continue in the current bear market it is unlikely that you will see much of a gain over the long run. My suggestion to you (and anyone reading this) is put it on your calendar to check your 401k. Make it a reoccurring appointment. Take 20 minutes at the end of each month and decide where the strength of the market is and how comfortable you feel with the equity markets at that time. If you work with an adviser, make him/her provide their insight. For those up on this year (which if you have been invested you should be up)... ask yourself... are you happy with a 10% return for the year? Then you may want to consider locking in some of those gains.
For those who subscribe to buy and hold... if the big money professionals and media really believed that... I ask you... who is doing all the selling that drives a market down???