Hmmm, like asking "when is a tomato too expensive?"
You need to know availability, season, crop production, quality, competition prices, consumer demand..............................
Or "How much money do I need for a vacation?"
Where are you going, where are you starting, how long will you stay, do you have a job, how many people are going with you, what luxury level do you want to enjoy..............
Are you open shoving 27o 9 handed UTG with 30 BB (OK I know, but to make my point) or Q9o from HJ 5 handed with 6 BB? Are you shoving over the top or as first in? Are your players that you are shoving on passive, loose, tight, aggressive, combinations thereof???
Some stacks of 20 BB can be open shoved, depending, some stacks of 5 BB should be folded depending..
Take some situations and post hand histories, that will be the best way, since the answer to your OP is "it depends"