I make sure to set the review cycle for each task or project to an appropriate amount of time. Some projects (especially those in the Someday/Maybe folder) have a weekly review set to monthly. Some are weekly. The default review cycle is set to review weekly.
When I go to my review mode, I only have to look at the tasks/projects that need to be reviewed in the present and near future (about 2 weeks ahead). I don't bother reviewing any projects/tasks that are beyond the 2 weeks ahead of me. Every 3 months, I do a major review of everything to just keep myself on track.
The Weekly Review is the time to start looking at any active and inactive projects and determine if they are still important to you. I sometimes have to get brutal and realize that a project/idea that I recorded in OmniFocus either has lost importance is no longer relevant. Then I would just delete it from OmniFocus. There's no sense in having clutter that just lingers on your OmniFocus list when it is no longer important/relevant.
I incorporated a little bit of Mark Forster's Do It Tomorrow (DIT) methodology into my OmniFocus/GTD system. It's using the idea of the closed list.
By default, I put any new projects/ideas in my Someday/Maybe folder because I already have a full plate of tasks that are "active". These projects have the "on hold" status. At least, I won't just be piling on new tasks/projects automatically and make my Context lists larger than it already is.
As I start completing tasks, during my weekly review, I will look at the Someday/Maybe folder and start looking for projects to activate. I take off the "on hold" status and change the project to active. Then I'll move it out of Someday/Maybe folder into the appropriate OmniFocus folder (usually any Area of Responsibility such as Work, Family, Charity). When a project becomes "active", they will start showing up in my Next Actions/Context view.
During my own weekly review, I would brain-dump all my projects/tasks/ideas into the Someday/Maybe folder and set these to "on hold."
I got this idea from Mark Forster's Do It Tomorrow methodology using the Closed List. Here's a quote:
Prioritising & Urgency. The DIT system creates a buffer zone between random inputs & your daily plans by using the daily closed list. Rather than immediately responding to every request, random idea, phone call, visitor, email & personal interruption, you make a decision about the urgency of the random event.
There are really only three levels of urgency:
1. Immediate. You have to drop what you are doing & respond immediately. Obviously this sort of interruption is NOT written down on your closed list. How much of your job or personal has to work like this? Very little actually.
2. Same Day. This level of response is not immediate but sometime during the day. There is no need to respond immediately as the interruption is not life-threateningly urgent. Donít turn this level of interruption into the immediate level of urgency!
Write down the new request on your closed list. It will be written down under the ruled line because the list got closed following the planning of todayís activities. Writing it down will help clarify your thinking about the priority.
3. Tomorrow. This is the ideal place to park items on your lists & works best for planning your day. As you plan your next day you know about this item & can action it at the most appropriate time.
Adding an item to the tomorrow list is ensuring you are not giving the item an unnecessarily high level of importance. You donít want to fall into the trap of always working on the latest interruption.
Since I already have a bunch of tasks already in my OmniFocus list, I just add new tasks into Someday/Maybe and automatically put them on hold.
Here's a a link that talks about the Closed List: