Realistically, how long could a young beardie live in a 20L tank? I know they need a much larger life style eventually but I'm looking at this as a starter tank...until I get my 250G set up next year 
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0.3.0 Dogs - Delaney, Darcie, Mali
2.1.0 Cats - Dante, Diesel, Dixie
2.0.0 Cockatiels - Toast, Waffles
1.0.0 Canary - Stewie 10/30/04 R.I.P
2.0.0 White's Treefrogs - Splish, Splash
1.2.0 Leopard Geckos - Joey, Phoebe, Rachael
3.0.0 Crested Geckos - Stubbie Mike, Chandler, Ross
1.0.0 Chinchilla - Poncho
3.0.0 Guinea Pigs - Rodney, Reese, Ray
1.0.0 Hamster - Harvey 11/4/04 R.I.P
Not to mention the plethera of fish:
5.1.0 Bettas
0.0.1 Goldfish
55 Gallon Community
29 Gallon African Cichlid
20 Gallon Marine
1.1.0 Ocellaris Clown - Jack, Diane
0.0.1. Neon Blue Goby - Cecilia
5 Gallon Guppies (& their friend Mr. Oto)
1.0.0 Boyfriend - Michael 




luckily my other half is VERY understanding.