It really boils down to how many REQ points you gain on a daily basis...I created a couple of spreadsheets that helped me keep track of what I unlocked and how long I could expect to unlock them all.
Here's a rundown:
Total amount of REQs unlocked via REQ packs: 1170
Spread of permanent unlocks:
Ultra Rare: 229
Disclaimer: These numbers ignore emblems and armor sets that are unlocked via "special" methods like commendations, seasons, special REQ packs like the HCS series, etc.
Before December, I was playing regular Warzone and maybe getting about 2 silver packs a day, or 1 gold. When I got serious about grinding out REQs, I maintained a 32 REQs per week, or 146 REQs a month, pace. That roughly translated to 4 silver packs per day, or 2 gold packs per day. I also switched over to Warzone Assault for about 1-2 hrs a day, which got me those packs. I also sacrificed a 20 to the Halo gods once a month. And finally, I stored all consumable REQs at a count of 10, any extra I sold off. I finally finished it all back in February, and have been able to maintain about a 200k REQ point monthly storage so I wouldn't have to grind when the updates dropped each month.
So. to answer your question...
Max REQs wanted unlocked: 643
Amount already unlocked: roughly 200
Time period: roughly 1 month (31 days)
REQ cost per silver pack: 5,000
REQs per pack: 2 (1 dedicated emblem spot, 2 permanent unlocks)
Listing that, we now get:
REQs remaining: 643 total - 200 unlocked = 443
Amount of silver packs required: 443 REQs remaining / 2 REQs per pack = 221.5
Amount of REQ points needed: 221.5 silver packs * 5000 REQ points per pack = 1,107,500
Amount of REQ points needed per day: 1,107,500 REQ points / 31 days = 35,725.8
Amount of Silver Packs per day: 35, 725.81 RP per day / 5000 RP per pack = 7.2