I do the same. My road and mtb are both tubeless but my rain bike (fendered) and when I get the Orbea off the trainer for the summer are both tubed. All run Conti GP5000s. Have to agree that maintaining 4 bikes with sealant would be a PITA, but two is far more manageable. Each bike has an underseat bag with full tire repair kit. Tubes in all, just in case.
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Road 🚴🏾♂️ & Mountain 🚵🏾♂️