It doesn't matter if you capture your own leads or buy them, you should ALWAYS verify the email address is good with a validation program. There are several reasons for doing this but I'll cover just a few.The longer you advertise ANY given product or service AND include your full contact information the more you are building your brand name and trust. You can brand YOUR name. A company name isn't needed in this industry to build a brand and trust.
Jumping from one business to another every 60-90 days brands you as someone that doesn't know what they are doing and shows you cannot or will not commit to anything so you would make a poor sponsor.
If you see a person advertising the same business for 6 months to a year or more that person is either making money or is working a long term plan that WILL make them money. This person could be someone to either work with, learn from or share success stories or failures.
Realize that when you are advertising to safe lists, traffic exchanges and other free or inexpensive advertising sources on the Internet you are often sending your ad to other advertisers.
Since your target audience is other advertisers, you had better be offering a way for them to build their current business or you won't have a chance of establishing that personal contact that you need before you have a chance to build a working friendship or business relationship.