This will probably be a controversial thread, but I think lifetime SaaS deals are not a good idea.
Here are three reasons why you may not want to offer a lifetime deal for your SaaS:
Here are three reasons why you may not want to offer a lifetime deal for your SaaS:
Lifetime deals turn your best customers into your worst customers 
The power users/believers of your product are the ones most likely to purchase lifetime plans.
They, by definition, become cost centers instead of profit centers and this can harm your relationship with them.

The power users/believers of your product are the ones most likely to purchase lifetime plans.
They, by definition, become cost centers instead of profit centers and this can harm your relationship with them.
Lifetime deals complicate billing 
For the foreseeable future you will need to code in edge cases for new features you are developing to give these lifetime users access, also becomes messy with features that cost you money (eg twilio)
This is painful to support long-term

For the foreseeable future you will need to code in edge cases for new features you are developing to give these lifetime users access, also becomes messy with features that cost you money (eg twilio)
This is painful to support long-term
Lifetime deals stifle growth potential 
The more value you give someone, the more money they should pay. That is how business works.
When you offer lifetime plans, you are eliminating this potential for growth.
Users getting a ton of value are usually willing pay a lot more

The more value you give someone, the more money they should pay. That is how business works.
When you offer lifetime plans, you are eliminating this potential for growth.
Users getting a ton of value are usually willing pay a lot more
Alternative to the lifetime deal
:
Annual pricing in my opinion is a much better approach to giving your biggest fans a better deal.
If you really want to up the ante, make it a 3 year deal, just don't commit to a lifetime deal because forever is a long time.

Annual pricing in my opinion is a much better approach to giving your biggest fans a better deal.
If you really want to up the ante, make it a 3 year deal, just don't commit to a lifetime deal because forever is a long time.
Side-note about AppSumo deals
There have definitely been cases where an AppSumo deal has done a ton of good for a business.
I think the best case for why you would run one of these deals is if you are a not very niche SaaS, preferably b2c as b2b generally require more support.
There have definitely been cases where an AppSumo deal has done a ton of good for a business.
I think the best case for why you would run one of these deals is if you are a not very niche SaaS, preferably b2c as b2b generally require more support.