Noob alert. I've been reading about the big deal that sending massive campaigns is, in terms of not getting banned, warming up IP's and so on.
The thing is that I have a site that deals with a few transactional e-mails, very low volume, so I'm using PHPMailer from my own server, never had a problem that I know of.
But then, when doing newsletters (to 5000 subscribers) I've been using MailChimp, basically because I wanted to avoid the html/css mess that e-mails are. Since their pricing is no good for our usage, I've been looking other options like MailGun, which also deals with transactional e-mails.
So I'm wondering, how can I know when I should consider stop using my own server and paying for a professional service if ever? What it really depends on? Is there a number or subscribers or any other tangible metric? It all seems very eerie.
Now that I've been setting up MailGun for transactional e-mails (so I can easily track opens, clicks and so on) I've been wondering those questions (i.e. "why am I coding to use an external API instead of this simple and seemingly effective PHP class")
The question goes to both newsletter campaigns (massive sendings at once) and transactional e-mails.