RAJ writes:

Do you think it would be wise to switch over to 410?

No. R22 is superior to R410 in every physical respect. The only issue is
availability of R22, which is to be artificially restricted by men with
guns (i.e., the gummint), not by the market. But this is not supposed to
happen for longer than your system today will last.

Go to epatest.com and get an EPA license and stock up on R-22 while it is
still legal. The people who did this with R-12 in 1992 made a fortune,
buying at $1/lb and reselling 5 or 10 years later for $50/lb.