You see there is an argument to take it in house but clients respond well to the guarantee of links. I don’t think they would actually care if you were to say “we’ve spent 20 hours on your account this month and achieved 5 links”.
So you also would want to checkout the number of outbound links from the URL they will be giving us a link on, and the domain’s existing link and anchor text structure, if it’s natural/spammy/over-optimised.
Buying links is still a great strategy, but the key is to tier out the path. Never have bought links point to your “money site”. Instead, set-up parasite pages on high DA sites that point to your money site. You may even want to add another tier if it is a high value client.