I just trim the top, I find it a PITA to replant things that don't have roots since I have MTS they uproot it.
exactly what I am talking about. Maybe I should try cutting every other stem of the same plant from the top or from the bottom and try to alternate at each trimming. When the base of the plant becomes an issue I can just cut a lot of the bottom out and regrow from a smaller plant like mentioned aboveCare should be used with certain plants if you trim the tops. This will result in bushier growth and the plant spreads outward. This can look attractive but then the lower part of the plant does not receive sufficient light and this can cause issues with the health of the plant at the base. A good example of this is Rotala Rotundifolia, it gets very weak and loses leaves at the bottom and then looks odd. This type of plant I pull up and trim the bottom and them insert back into the substrate.
This makes sense too. I don't think I would let it get to the gravel line for most plants but I could do this and stagger the plants lengths so as a whole the tank still looks healthy an l;ush.You can stretch replanting times by trimming one node lower each time. Eventually you start getting down towards the gravel line and it's time to replant. If you keep trimming in the same area, you eventually find yourself throwing away 5 gallon buckets of rotala stems every couple weeks. I like to cut taller stems back about a foot or more each time so you can go a couple weeks before you have to trim again. This of course, is dependant on tank height.