If you buy keyword specific domains, you're really buying the type in traffic.  I use the URL builder and redirect through that URL so you can see how much traffic your getting from the keyword domain.  There seems to be no rythme or reason to what keyword domains deliver traffic and what don't.  By tracking traffic with the Google URL builder you get a feel for what names are giving you traffic and which are not. ie. the plural, the singular, two words, three words, the possessive, etc.
While getting a new domain name will give your site a clean slate and allow you to start a fresh marketing campaign, you may not be aware of the fact that some expired domains come with a high Page Rank value. A company that buys such a domain will not have to work so hard on website promotion and backlink building techniques. Thanks for updating this really informative post!
Official marketplaces offer a third possibility for domain traders to peddle their product. Domain marketplaces, such as Sedo, GoDaddy.com, or BuyDomains.com, link potential buyers with domain holders hoping to sell their prized virtual property. These platforms function as a kind of domain real estate agency and are known to demand somewhat high prices for their services.

A rule of thumb that I follow is when I purchase a domain name I have to believe that I can flip it for a 100% profit.  So if I spend $500 on a domain I need to feel like I can sell it for no less than $1,000.  This way, even if I’m wrong in my estimation I still have some room to still turn a profit.  And if worse case comes to worse case I’ve sold domains before for a $0 profit (it happens even to the best of us).
Karn Jajoo heads the premium names program for Radix’s domain extensions: .WEBSITE, .PRESS, .HOST, .SPACE, .SITE, .TECH, .ONLINE, .STORE & .FUN. Radix has made more than $1.75 million in premium domains revenue in 2017 thus far, including the biggest nTLD sale of all times — casino.online, and the sale of business.site to Google for it’s free website builder, Google My Business. Karn considers himself a new gTLD evangelist and has had articles published in The Next Web, Website Magazine, & CMO.com.
You can still buy two word or three word domain names incorporating your target keywords. Moreover, there are millions of domain names out there which haven’t been used at all and are bound to expire soon. All such domains keep coming back to the domain marketplace. What more, there are useful tools available to research and filter through such expired domains.
Domain names are hot commodities in today's tech-centric world. The $16 million sale of 'insure.com' to Quinstreet in 2009 may have set the world record, but even lengthier domain names are routinely sold for hundreds of dollars every day. The result is a unique opportunity for investors to invest in domain names that can be sold for a profit in the future.
What about option #4 - Redirect your existing domain to the old domain? I bought an old domain that is 100% relevant to my current domain but currently has with very little content. It did have more content fours years ago. The old domain is 13 years old, pr=3, while my current is 7 months old pr=1 and a decent amount of content. The old domain I purchased was not expired though and I do not know if this makes a difference. What are the pros and cons of option #4? Am I correct to think that option #1 would result in no benefit from the old domain's age value and if so why is it not listed as a con, a MAJOR one. Its hard to believe that a 301 using option 1 would give my existing domain 13 years credit but I'll take it if it does.
When a domain name that was previously registered expires, it goes through a grace period that allows the previous registrant one last chance to reclaim their domain before it becomes available to new buyers. If the previous registrant still has not renewed their domain after the 77 day deletion process, the domain name will officially expire and enter the Aftermarket.
Also note the Expired Domain Plugin is a lifetime “per user” license, so if you have multiple ScrapeBox licenses registered to the one email address purchasing the Expired Domain once will activate the plugin for all your ScrapeBox licenses with the same email for life. The plugin is a one-time payment and is not a monthly or yearly subscription, all updates are free.
So how do you develop that instinct? NameBio maintains a database of over 500,000 historical domain sales (as of writing this post). They have interesting filtering features by which you can narrow down domains by price range, date sold, keywords and more. Simply sifting through the listings on NameBio long enough will quickly develop your domain appraisal “instinct”.