Your task is not to convince affiliates to log every day. Your task is to support them, give help them, courage them and be their guide.
If they are serious in their attentions to do this job, they will find out that everyday logging is necessary.
If you don't log every day, you can't make progress, and this is one of the first things that you should understand.
Tell them this, and, if they are serious, they will accept it.