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You need to do an optical test at least on the primary, (either Foucault, Ronchi, Star or all three). Requires minimal equipment but some knowledge on how to interpret.
The advantage of re-coating is that the focal length of your mirror will remain exactly as it was which isn’t guaranteed if you buy a new one although there could only be mm in it. If your tests indicate you have a good optical surface then re-coat since you won’t be entirely certain what the optical surface accuracy of your new mirror is until you test it.
If it was a custom mirror made by a reputable optician, then re-coat for sure. Given that it is a mass produced mirror you could buy new and get something of equal or better or worse quality, (I’m talking optical quality without the blemishes). These days mass produced mirrors are very good but quality control is not so good but that is the price you pay (or not pay) to get a larger cheap mirror.
I have a Meade 16” f4.5 Lightbridge that I am very happy with. I too have a 10.1” f6.4 custom figured Newtonian by a master optician that simply excels in good seeing giving pin point star images. The 16” pulls in a lot more galaxies simply due to the aperture which is what I enjoy most about it. I also have a 10” f4.7 Skywatcher which I bought the kids used. It is a fun ‘scope that provides pleasing views of all types objects in the night sky.
If re-coating the primary get the secondary done at he same time, (should be minimal extra cost), or buy another cheap (GSO) secondary or expensive (Antares) secondary, choice is yours. I wouldn’t glue an expensive secondary, rather get a proper holder with a lip. I’d stick with the Meade secondary too and get it re-coated although having never to deal with a glued secondary I’m not sure on the pros and cons of removing them from their glued holder.
I got my 10.1” f6.4 and 6” f5.5 and 1.83” secondary re-coated in 2003. Still look like the day I brought them home. Also bought a 2.14” secondary from the guy doing the coating that day. No longer in business so I’m not sure where the best spot to get it done these days but I’m sure someone else will chime in.
If you buy new then keep your old mirrors (pri/sec) until you’ve fully tested your new ones. If you’re happy with them then off load your old ones as there’s always a buyer out there, or get them re-costed at a later date and keep them with the Lightbridge as a set. Note if buying new the focal length will have to be a close match otherwise the focal plane won’t be where it should be and some simple or not so simple tweaking may be required.
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