Sometimes the answer to this question depends on how much stock of either the company you are purchasing has on hand. But what, if any, is the real difference between the two when discussing fencing in particular? For this discussion we are focusing on the pickets themselves, as opposed to the post or stringer as we typically install metal posts with treated 2X3 stringers or treated 4X4 posts with treated 2X4 stringers.
— Cedar has (common) Redwood beat in the price category, but not by much depending on where you live or where you are buying.
— Cedar is a light yellow wood while Redwood typically has an earthier brown/red tone, & each will definitely give you a certain look if you are planning on leaving it raw.
— If you are painting or staining the wood fence after installation Cedar may be the better choice over Redwood because of the price difference.
— As for strength & durability, if we use the Janka hardness test Redwood is the clear winner, but unless you are using your fence to catch errant foul balls Cedar (for pickets) should be more than satisfactory.
— While most fencing contractors will recommend redwood to prevent termite damage, Cedar & Redwood contain tannin, which is a natural insect repellent, but Redwood contains more & may outlast Cedar in a head to head race to rot.
As you can see the differences between the 2 types of picket are not so large & the choice will often come down to general appearance goals & price!
Don't find out the hard way why maintenance on fences is key! A few hours 2-3 times a year could be the difference between wood fencing that last for 20-30 years or a fence that needs to be replaced too soon.
Every 3-6 months you should check your fence for peeling, splintering, mold or breakage, especially at the base of posts & pickets, & the tops of stringers where water can pool or collect. If you have a vinyl fence summers can dry out & create brittle components like caps that need to be inspected.
Also look for signs of termite damage & infestation. If you find signs of termites, then you may want to consider spot treatment by an exterminator, especially if the fence is attached to your home, as you may have a larger undiscovered issue.
Next, depending on the style of wood & fence, you may want to sand off rough edges or protruding splits, these can provide an entry point for wood destroying insects or dry rot fungus.
The next few procedures may take a bit longer; however, they only need to be preformed every year or two. Painted fences may start to look old when they start peeling & become flaky & chipped, & the loss of the paint's protection will lead to weathering & insect entry more readily. Scraping, painting & sealing can lengthen the life of your fence. First, scrape away flakes & chips before painting. Then use a primer & an outdoors paint to paint the fence. Afterwards, or instead of painting if you prefer a natural look, you may want to seal the fence with a clear or transparent product to help preserve it.