One of the key aspects that you have to consider has to do with the allocation of human resources to marketing tasks. Carrying out an email marketing campaign involves a series of processes to which you have to dedicate a minimum amount of time. In summary, the basic steps to create an email marketing campaign are:
1. Preparing the database.
This includes creating the segment to which you will direct the campaign, managing unsubscribes, preparing the fields in case of personalization and the treatment of office 365 email list bounced emails and once the sending has been carried out.
2. Validating the HTML assembly.
Before launching an email marketing campaign, you must verify that the HTML code is correctly formatted and that the delivery will not be penalized. If the validation tests are not satisfactory, you will have to review different aspects of the code. You can download some practical advice from this link.

3. Sending tests.
You should also carry out sending tests on representative email addresses in your database: Outlook, Gmail, Yahoo, Hotmail, etc.
If the tests detect that in some of the providers the message is filtered as spam or the presentation of the creative is altered, you will have to make the necessary adjustments to solve the problem.
These steps are the minimum necessary, although the process can be extended if we introduce tests (A/B testing or multivariate), or if we want to adapt the message to the mobile inbox for example.
The average time that a marketing technician can spend preparing and executing an email marketing campaign can be between 2 and 4 hours depending on the user's experience and the tools available.
ALTERNATIVES
The execution of email marketing programs can fall to someone from the marketing or online marketing department, or even someone from technology. It is necessary to determine whether the cost/hour is not higher than the cost of outsourcing to an email marketing agency .
Another option, valid for organizations with short marketing structures, is to outsource the execution of campaigns to an email marketing agency . The main advantage of this alternative is that the organization's internal resources are not blocked in tasks that provide little value. In addition, the expertiseof the email marketing agency professionals guarantees a correct execution of the processes.
In conclusion, we can say that the greater the digitalization of marketing and the fewer internal resources, the more interesting it will be to use an email marketing agency . The lower the level of digitalization and the greater the capacity to allocate internal resources, the more appropriate it will be to dedicate internal resources.