Spell recovery old and new + cantrip chat

Flipping through the ad&d DMG in a moment of private gary worship I found a long forgotten table on pg40. Recovery of spells did not require 8 hours or rest and/or 8 hours of study. 

All spellcasters require rest time but the amount is based on the level of the spells you want to be able to relearn.

Spells Lv 1-2 requires 4 hours rest
Spells Lv 3-4 requires 6 hours rest
Spells Lv 5-6 requires 8 hours rest
Spells Lv 7-8 requires 10 hours rest
Spells Lv 9 requires 12 hours rest

Ten you reqire 15 minutes of time per level of spell you want to recover
so if i want 3 first level spells and 2 second level spells back so it takes 4 hours rest then 15min x3 and 30min x2. So 5 hours and 30 minutes. But if oops i want a third lv spell too then i need 6 hours rest and two & a half hours to recover spells.

We used 8 hours plus 15/min per spell in AD&D for some reason as kids. 

I think this has some good benefits. It's fiddly but has some benefits.
-It makes high-level spells more valuable resources and slows those wishes per day a bit.
-you could renew your low-level spells with less effort
-it makes downtime harder and more costly time-wise
-Sometimes you could get extra castings a day of low-level spells fairly quickly
-it will make players burn low-level spells more
-makes low-level spells cheaper and high-level ones cost more in a healing swaetshop for clerics

I have cantrip slots, so I am amending the above table to include cantrips.
-not infinite 5th ed ones, and not better than using a dagger
-beginner zero-level casters used to start with one cantrip, and when you could do 4 you would swap them for a 1st lv spell and you were a 1st level caster with your one spell (maybe more if a preist). You used to be able to swap a 1st lv spell for 4 cantrips. Some retro clones have zero level spell column just like other spells which is my preference. There were tables with -2 level and -1 level before zero level for spell casters and cavaliers.

Spells Lv 0 require 2 hours rest
Spells Lv 1-2 require 4 hours rest
Spells Lv 3-4 require 6 hours rest
Spells Lv 5-6 require 8 hours rest
Spells Lv 7-8 require 10 hours rest
Spells Lv 9 require 12 hours rest

So I'm tempted to use one ten-minute turn per spell level as this is a basic standard D&D time unit in old games so fitting in with this and maths is easier (total levels add a zero on end in minutes or six slots is one hour.

I might add a column on the castable spells table with time to fully recover all slots and cost of components one.

Im really tempted to let maybe cantrips to require one minute or zero time outside rest. I dont like infinite cantrips so good why would you ever use a weapon? My pissweak cantrips can be handy and players have done some weird things to enhance cantrips but making them more usable but not as good as 5th ed usable. If I run a zero lv wizard school game, this will be more fun. Also good for my Goat Quest games of animal cult investigations, where open gate was a popular spell. As I have lots of weird magic skills for players to mess with I had a character for 5 skill slots could cast a extra cantrip each round, got +3 damage on a single cantrip and could convert a 1st lv spell into 4 cantrips so he did a extra d3+3 damage every round plus another spell or do it twice. It sounds gross but was a big investment.

I will run this by the players. An amended spell progression table with time and component cost will help. Material components may end up as disposable vs fancy foci that are cheaper, but losing them is time-consuming to recover items.

components:
Arcane - minerals, magic critter parts vs wand or staff or dagger foci
Divine - holy water, holy oil, wafers, wine  vs holy symbol, shield or weapon foci
Nature - herbs and animal parts vs sickle or staff or live snake foci 
Mentalist - drugs or crystals vs jewellery or a staff foci

I had a 5th-ed cleric drop all weapons at 3rd lv and my dm noticed at 9th lv when I couldn't be bothered with opportunity attacks because I didn't want to touch dirty monsters, but i did keep a shield. Those weapons were better in the hands of poor people. Maybe if i had a magic weapon, I would have used it.