Removal companies see every tree as a removal. That math is backwards for most Conroe yards, where the mature pines and oaks are a real share of what the property is worth. A healthy 80 foot shade tree cannot be bought at a nursery at any price, so the first question here is never how fast it can come down. It is whether the tree can be kept.
The threats in Montgomery County are specific and worth knowing. Bark beetles, including the southern pine beetle the Texas A&M Forest Service monitors across East Texas, kill stressed loblollies in weeks. Post oaks tolerate almost no root disturbance, which is why they die a few years after driveways and additions get built over their roots. Water oaks hollow out with age and hide it well. Each of those has a different answer, and none of the answers is a guess.
Health work here starts with a walk around the tree and ends with a plain recommendation. Sometimes that is disease treatment or beetle and borer response. Sometimes it is deep root fertilization for a tree struggling in compacted soil, cabling and bracing for a split-prone fork, or a root barrier to end a war between a tree and your foundation. And sometimes the honest answer is that the tree is done, in which case you want removal before the weather decides the schedule for you.