Shed cladding - to re-do or not to re-do

Hi All, I'm looking for opinions.

I have an old shed that I am looking to convert into a workshop.

The shed has been clad in treated tongue & groove (vertical) some years ago (not by me). As you would expect, as the wood has weathered and aged, gaps have opened up between the boards. There is no membrane or anything like that, the boards are simply nailed to the frame - and the inside of the frame is lined with ply.

I am considering a few options:

1. Clad with featheredge board over the top. I think the best solution, but I'm not really keen on the cost or effort involved (its a reasonable size shed).

2. Remove the tongue & groove boards and shift them all up slightly so they now fit together properly. Fit a new board on the end to fill the gap. Is this feasible, or are they likely to just break during removal? More hassle than its worth?

3. Leave it as is and kit out the inside as a workshop. Do the gaps really matter anyway? I am thinking that even if a bit of water does get inside (between the cladding and the ply) then the gaps provide decent ventilation so will just dry out anyway and therefore not rot?

4. Any other ideas??

Worth noting that I think the gaps have been there for a number of years now and there does not seem to be any sign of rot or water damage.

Any thoughts welcome. Many thanks.

Horizontal feather board over the vertical would probably be best. It would at least add an extra layer against the elements.

vertical boards (always?) rot from the bottom, where they are near the ground.

this means that every board rots.

With horizontal cladding, only the bottom one or two boards get excessively wet. You can replace them if they rot, and you can drench the replacements in wood preserver. You may have scope to have an impervious material for 250mm or so above ground level, such as a dwarf wall or metal cladding. I got some made-to-measure stainless kickplates and painted them brown to blend in. Brass or stainless screws make it easy to replace the boards, and you can cut and treat a few spare ones for future use and tuck them into the void.

Shiplap is not fully proof against driving rain. You get a better results if you put roofing membrane or felt behind the battens and lay it so that any water runs harmlessly out the bottom without wetting the cladding. This will also block draughts and spiders, and by keeping damp out will reduce risk of rot in the studs and ply lining. If you want, you can add insulation on the dry side.