English translation:
if only…then
as long as…
only thing … needs for … is …
Structure:
Verb[stem] + さえ + すれば
Verb[て] + さえ + いれば
Noun + さえ + Verb[ ば ]
いAdj[く] + さえ + あれば
なAdj + でさえ + あれば
Explanation:
[Aさえ…ばB、A is the only/minimal condition for B to be realized.]
たら can be used instead of ば form
but it is rarely the case.
Hey, sorry for a long time it took to answer, I have noticed the post today 
I have added it as an alternative answer. Basically, 暇 can be also treated not only as な adjective but also as a noun.
Cheers 
It would be great to have some examples added so that each structure point has at least one example. Some examples for adjective structures are missing right now, and I don’t see them often enough in the wild to feel comfortable with them just yet.
Is てさえいれば a counterpart to ている? It’s not quite clear from the write-up. What is the logic behind すれば, いれば, あれば in general?
