I do it like this: Drive up to the parts store, get new oil and a filter, drive back, let it cool for a half-hour, and then drain the oil. It’s my understanding that warm oil flows better and will get more gunk out of the engine, so this way I automatically warm things up. I don’t do it hot so that the oil has a chance to drain out of the top-end. A rubber glove is often used just in case it’s hotter than I anticipate.
Never had a problem doing it this way. However, as was said before, it’s most important that it simply gets done regularly. The temp of the oil matters little.