Turtles - Massive tank/massive space for external filters, people don't realise just how much turtles shit and polute their own water, so the need for external filters is esencial. They also require a hella big tank to live proper and full lives, even when there about 2-3" long, they should still be living in something 36"x15"x15" at a MINIMUM. Water perameters have to be perfect too or you get one sick turtle, maturing the filters to break down the crap the turtle puts into the water. Plus there pickier on food/its more difficult to get there UV requirements sorted up as the UV dissapates through the water, giving the chance of Metabolic Bone Disease if it's not basking enough. Torts after a year or so need to be outside really 8 or so months of the year. Like you say, it'd be unfair on the tort if you can't provide for them. Another trouble with torts is ensuring you have the weight/length right. Dispite the fact they will sit and beg for more food, you have to resist or you could be forcing your tort to grow, leading to deformation in the growth. Monitors Lizards are meant to be fairly cool to keep, they show affection like beardies after a few months but you have to introduce yourself to them carefully over a few months to ensure you don't startle it or make yourself a threat to them. When handling thou your best off to keep a bottle of vinegar near by. When they bite they can lock their jaw, so its a case of pour vinegar into the mouth untill its off! Its a preety big undertaking with a Monitor thou, looking at care sheets, a sutible viv needs to be atleast 8foot x 3foot then whatever height to accomodate the heat needs.