Maintaining trails means assuring that they achieve their objectives over time. Unlike past concepts of maintenance (i.e., preserving and keeping trails and related facilities in their original condition) the guidance system maintenance concept is one of responding to need and to changing user interests; to upgrading some trail segments, to allow some to stabilize and "age", others to decline within limits of a large set of objectives (including cost limits). The objectives include the large array of conventional trail uses and safe, low-effort passage. Maintenance can be completely stopped only on trails that are completely closed.

Trail maintenance will be done by volunteers and by contract work wherever possible. Maintenance will be scheduled for a minimum of every three years but will be done more frequently in segments where there is greatest change and use rate. Within the U.S. Forest Service the concept of a "recreation opportunity spectrum" (ROS) is used. Trails are placed in six ROS classes. There are notable overlaps. The classes may suggest levels of use or intensity that may influence the frequency or intensity of maintenance work. The more primitive, generally, the less the level or intensity of maintenance:

Class I - Primitive II - Semiprimitive Non-motorized III - Semiprimitive Motorized IV - Roaded Natural V - Rural VI - Urban (this level includes specialized bike trails and those for the handicapped)

Most trail work includes removing windfalls, brush growth, rock falls, and erosion gaps. Windfalls are major problems. They need to be removed along with trees near trails in a condition likely to fall. Trees across a trail will have a section removed so that the remainder of the log is farther than 4 feet from the center of the trail. Cuts are made at an angle to allow the section to roll free with minimum worker effort. The uphill cut is usually made first. Later cleanup should reduce needs for further work and stabilize trail-side soils.

Brush is usually cut back from the trail to the original clear-line. Hand tools, power saws, or herbicides may be used on brush less than three feet tall.

Tread is graded by hand, or by horse-draw or mechanical grader to remove effects of erosion, use, or windfalls. The outslope is restored; water bars and dips are cleared; drainage construction is repaired or expanded. Culverts are cleaned. Bridges, steps, and retaining walls are repaired. Major work after 5 years can usually be viewed as new construction, not maintenance, and may require a substantial budget. Replace puncheon as needed; concentrate or drainage work to reduce need.

Work plans include crew leadership and organization; equipment and supplies; schedule of work; schedule of travel; trail camp location and provision; fire instructions; and records of work.

Numbered trail markers can improve control and allow users to report areas where maintenance effort may be appropriate.

Safety is vigorously promoted. Maintaining trails is dangerous work. Safety training is essential; all crew members must be safety conscious. Each member is the safety coach of the entire crew. All crew foremen and key members need first aid training. A 5-person kit needs to be available at the work site at all times. Replace all items used at once.