Leads are expensive to generate. Even "free leads" from inbound and content marketing, aren't totally free - you have to factor in costs from the marketing department's salaries and resources.
On average, it costs $26 - $50 for most businesses to generate a lead. Some industries, like Financial Services or Technology, could spend even up to $100 per lead. This cost is the blended average of marketing personnel salaries, paid ads, events etc.. 
Perhaps this is the reason why the entire marketing industry is obsessed with increasing lead conversions via websites by fractions of percentages, and squeezing ever incremental increases in marketing yields.
Yet, the irony is that most companies waste up to 71% of their Internet leads.  By making the following mistakes -
-Not reaching out in a timely manner
-Not reaching out at all
-Sales team cherry-picking leads
-Not following up enough and re-engaging stale leads
Are you making any of the above mistakes?