You're finally putting up privacy fencing after three years of your neighbor's dog terrorizing your yard. Or you need a fence for a pool (often legally required in Maryland), or you're selling and the realtor wants curb appeal. Wood, vinyl, aluminum, chain link - each has real tradeoffs.
Wood fencing looks great but needs treatment every few years and will eventually rot at the posts in this climate. Vinyl is low maintenance but can look cheap if you don't get a quality product. Aluminum is good for decorative perimeter fencing. Chain link is the honest choice when you just need containment without the pretense. A good fence company will explain all of this without pushing you toward whatever they have in stock.
Wood privacy fence typically runs $20-$40 per linear foot installed. Vinyl runs $25-$45. Factor in permit costs - most jurisdictions in the DMV require them for fencing, and yes, you should pull the permit. Red flag: anyone who says permits aren't necessary in your area without actually checking.