Let’s also not forget that HP rains down on us so often that lack of HP is just a sign of poor spending.
Your average PvP gives out 25 HP at 400, 600, & 50 at 800 points. Granted 800 is pushing it without shield hopping, but it can be done.
Most PvE events include some HP rewards in the progression as well (why this Heroic doesn’t is beyond me), but those are usually variable based on the length of the event and are sometimes rewards at regular nodes in the event.
S.H.I.E.L.D. Simulator includes 25 HP at 1000, 1500, and 1900 points.
Season Progression includes HP as well (again, this is still fluctuating.)
Shield Resupply offers 25 HP roughly every 10 days & 12.5% chance of 50 HP on the random days.
If you are placing well enough to earn covers for a new character, you are also earning 25-100 HP per event for the Rewards (and Sub-Events for PvE). If you have an active alliance of more than 10ish people, your Alliance should be pulling in an extra 25-50 HP per event, more if you are in an alliance that is earning covers too.
And finally, did you collect all the HP in the Prologue?
Don’t waste money shielding if you are struggling with HP. Most times, IF your score would hold out for the level you are currently you’ve spent 75 HP to earn 25-50 HP more than you would have not shielding, that’s a net loss of 25-50 HP. If it’s an event that would give you your 13th cover for a character that is understandable, but even then is that shield guaranteed to keep you in that position? Then answer is typically “NO.”
I’ve also mentioned that buying covers (EVEN YOUR 13th one), is a really bad deal. That HP could be used for multiple roster slots.
It’s your choice how you spend your HP, but they give us a lot of free HP. If you are struggling to buy a roster slot, perhaps you could change where you spend your HP.