I can't speak for Old Regulars entirely, but knowing that our practice in such things is very similar, I can tell you what many Primitives do, and what was done to me.
I started out by getting up, at the behest of our then Pastor, and talking scriptures from about the age of 17 along with another young man in the church. After several years, and another Pastor, I was asked more and more to take time in the stand. Beginning a couple years ago, as I began to grow and a calling for the ministry became more apparent, I start to be put in the stand by other churches during their annual meetings and such. This was while my Pastor was present at those places to watch over me, so to speak. Since at that time I had not be officially liberated by the church yet, the Pastor was sort of responsible for me, if you want to call it that.
After doing this for about a year or more, the church felt that the time had come to liberate me (in April 2006). This was basically just an outward showing by the church that they do believe that I have a call to the gospel ministry. I am now able to accept appointments at different churches and preach wherever I may be asked without the supervision of my Pastor. I am still in a growing and learning stage and I'm not yet ordained. I can not perform the ordinances of the church.
I don't know how long I will be liberated before the church sees fit to call for my ordination. It may be another year (I hope it's at least that long because I don't feel ready) or it may even be 5 years or more. I know of men who were liberated before ordination for 10, 15, or even 20 years or more. I see that there have been men ordained before simply because they had been liberated for many years, yet probably didn't have a true calling, which is wrong. I've seen men ordained after many years because of doubts they had within themselves to live up to holding such a position. I've even seen men ordained only after many years due to personal conflicts they may have had with members and/or other ministers within the church.
I hope I don't fit into any of those categories, but I'd much rather be ordained a little later than necessary than to be ordained before I should have been. I've seen that happen as well, and it can really ruin a man.
Basically, when the Lord says it's the right time, hopefully the church will feel the same, as will I.
I know there are many PB churches that do not practice liberation/licensing or preachers before ordination, making it more of an unspoken liberation. I see this as another step in my growth and I think liberating a man before ordination is a good thing for his growth and to make evident/public that growth and calling to other churches.
The way I see it, if my home church does not see a calling to preach, then what business wouldI have preaching for other churches? If my home church does see a calling to preach, then how else are they to make known that calling to other churches to then allow me to preach for them and test that calling themselves?
My church is not in an association, so we do not have the burden of waiting for the meeting time to make announcements such as this.
I believe we are pretty close, if not right on, to the practice that most Old Regulars have in this regard. An OR brother can correct me if I'm wrong on that.
God bless.
James