best thing i can tell you is to watch the forums. My updates end in oct. If you are up to date and happy with the tool I would wait a litttle while and check the forums. If the software improves then you can justify another year of updates. If not you still have what u got. Just my opinion. 

   I seem to remember posts about guys trying to update  everything very close to the end of their subscription and sometimes it doesn't end well with stuff getting corrupted or something, and support cannot remedy the situation before expiration and you are forced to buy update.
    To play it safe I wouldn't try to upgrade anything closer than 30 days from the expiration date. Support seems overwhelmed and issues seem to go unresolved for weeks on end  ESPECIALLY IF THERE HAS BEEN  IS A RECENT MAJOR SYSTEM UPDATE. It would be very likely that even if you backed up all your software when  you have the  earlier system version , then I believe your MaxiSys will reject , and is not going to work off  backup software from an earlier SYSTEM VERSION (earlier vehicle make software versions backups of same system version # probably will  work if you needed to roll back a version for a car make). Maybe Support could weigh in on here whether or not what I suspect might  be true is correct or whether it is not. Support Please  give advice about how to properly make a back up version of our  software of a Maxi Sys or Maxi Das that will not let us down if we need it!

 backup, backup, backup, everything then choose which version works best rumor has it its getting better i haven't updated for a while due to obvious reasons,
  but support NEVER tell us exactly whats added or removed which is incredibly stupid of them what do we use a bloody crystal ball.

 We have notes for each software upgrade, please click on the ! icon to check.

On the other side, we don't mean to delete or reduce any existing functions in new version. Some feature may be missed when we making some interface change or function integration.  For such problems, we hope you can give us problem details and upload datalog if possible. We will ask engineers to compare old and new version and give you reply.  we just wish you could give us more details so that they can arrange field tests sooner.